Vol. 21, No.4 (Suppl, 1) Printed in Great Britain
International Journal of Epidemiology © International Epidemiological Association 1992
Chapter 3 Maternal Alcohol Consumption and Child Development F FORREST, C DU V FLOREY AND D TAYLOR
INTRODUCTION In the previous chapter the evidence of a relation between alcohol consumption during pregnancy and the immediate outcome of pregnancy was reviewed. It was concluded that although adverse outcomes were regularly seen at consumption levels of two or more drinks a day (about 140 g/week absolute alcohol). below this level results were inconsistent. In this chapter we ask whether this is also the case for child development. The term 'moderate alcohol consumption' has been used loosely here to mean levels of drinking that would be socially acceptable. but does not carry any specific connotation of quantity. The studies of child development have been based on the hypothesis that the offspring of moderate to heavy drinkers would have similar qualitative deficits to those seen in studies of the newborn and the central nervous system deficits of the fetal alcohol syndrome (FAS). Authors have considered a variety of outcome measures including behaviour. mental and physical development, and learning ability. We have reviewed the types of outcome measure related to alcohol consumption and have attempted to find an approximate level of intake which is usually associated with adverse outcome. We have drawn on a previous review! for the 'threshold' values suggested below.
born between February 1975 and March 1976 to white, married, middle-class women selected from a consecutive sample of 1529 pregnant women. The cohort was selected before delivery to include 250 of the heavier drinkers and smokers and 250 of the light drinkers and abstainers. Those who conducted the infant assessments were not involved in the sample selection. The sample size varied between sub studies due to their different lengths and timings, the number of eligible infants delivered during the period of each substudy, the number of hospitals at which the substudies were conducted and factors such as examiner illness and equipment failure. The subsamples were not randomly chosen from the screening sample but it was not made explicit how the samples were chosen. Furthermore. the initial cohort of 500 children could not be maintained over the duration of the study so others in the original 1529 who were available at the time were recruited to make up the numbers. Quantity, frequency and variability of alcohol consumption were obtained by a single interview with the mother in the fifth month of pregnancy. She was asked about drinking in two time periods: in the month or so prior to recognition of pregnancy (termed early pregnancy in the publications) and around the time of interview, or mid pregnancy. The early pregnancy values were considered to represent prepregnancy behaviour on the assumption that the drinking pattern would not alter until after recognition of pregnancy (A Streissguth, personal communication). Consumption was quantified using average ounces of absolute alcohol consumed per day. Multiple regression analysis was used to control for the effects of
THE SEATTLE PREGNANCY AND HEALTH STUDY Streissguth et al.? initiated the earliest and longest follow-up study on the effects of moderate alcohol consumption. The Pregnancy and Health Study sample consisted of a follow-up cohort of 500 children S17
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Studies of development and behaviour from shortly after birth up to the age of 7 years are reviewed. Maternal alcohol consumption above 150-200 g/week is related to behaviour in many studies, but below this level there is little epidemiological evidence of association. There is no evidence that the levels of consumption associated with adverse behaviour are lower than those associated with adverse pregnancy outcome.
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potentially confounding variables including smoking, caffeine, drugs, diet, obstetric history and demographic characteristics. Maternal alcohol consumption and its relation to child development was studied at three different stages of development: infancy, during the preschool years, and at 7 years of age. All outcome measures were conducted blind to knowledge of maternal alcohol consumption.
Infant and Child Development Studies Mental and motor development at 8 months were examined in 462 infants? using the Bayley Scales of Infant Development. The children's developmental indices were significantly lower if their mothers had consumed 165 g/week or more in early pregnancy, after controlling for confounding variables. Body size was measured at 8 months in 453 of these infants." After
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Newborn Behaviour Newborn behaviour, habituation, learning and sucking pressure were analysed for their relation to maternal alcohol consumption in both periods for which data were collected. On the first day of life, behaviour was measured using the Brazelton Neonatal Assessment Scale in 124 infants, selected according to level of maternal alcohol consumption." Alcohol consumption grouped according to consumption in both early and mid pregnancy was significantly related to five of 16 behaviours and to the proportion of time infants tremored, positioned their head to the left, had their eyes open, touched their hands to their face and decreased the amount of vigorous body activity. Habituation, also assessed by the Brazelton Scale, was investigated in 417 infants." Drinking in mid pregnancy was significantly related to two (poor habituation and low arousal) of six dependent factors after adjusting for confounding factors. Learning and sucking pressure were measured on the second day of life. Learning was investigated using a head-turning conditioning task with 225 infants and a sucking task with 80 infants.! Moderate alcohol consumption in early pregnancy and moderate to heavy cigarette consumption had an interactive adverse effect on the infants' performance. Sucking pressure was electronically recorded in 151 infants." After control for the effects of possible confounding variables, heavier maternal alcohol consumption during early pregnancy was significantly related to decreased pressure. The effects were associated with levels of maternal alcohol intake of 10z absolute alcohol!day or more (~165 g/week) in those papers which presented data for women in different consumption categories. I
adjusting for the effects of confounding variables, maternal alcohol consumption in early pregnancy at possibly 160 g/week was related to lower infant weight and length and less strongly associated with smaller head circumference. The relation between alcohol consumption and infant size was weaker at 8 months than at birth. Attention and reaction time was investigated in 452 four year olds using a computer-controlled vigilance task.? Heavier maternal alcohol use in early pregnancy was significantly related to poorer attention and increased reaction time but not to activity, after adjusting for controlling factors. A second analysis of four year olds reported results from testing 421 children with the Wechsler scales. The mean IQ was 5 points lower in children whose mothers drank more than 250 g/week in early pregnancy than in children of mothers who drank less. 10 The continuing adverse effects of maternal alcohol consumption on attention and reaction time was demonstrated in 475 seven year olds (6.5-8.5 years).!' The sample size was larger than at the four-year follow-up since additional subjects were added to the cohort from the original screening sample to keep the sample size at around 500. Alcohol consumption during early pregnancy was significantly associated with attentional deficits and slower reaction time, but was unrelated to time spent in motion. Ratings of distraction were related to alcohol consumption of ~250 g/week. A more sophisticated analysis of 158 outcomes, with many covariates, confirmed these findings, but did not allow the identification of a potential threshold value for alcohol consumption. 12,13,14 A further analysis revealed that mothers drinking ~ 165 g/week in mid pregnancy had children who on average had a deficit of 7 IQ points and children of mothers drinking five drinks or more on any occasion (binge drinking) had learning problems significantly more often than those whose mothers drank less." Findings from the Seattle Pregnancy and Health Study indicate that maternal alcohol consumption during pregnancy is related to neonatal behavioural problems, poorer infant mental and motor development, smaller infant size and behavioural problems in preschool and school-age children. In as far as the data in the papers allow identification of a possible threshold for alcohol consumption, the lowest is about 160 g/week for growth but for the mental and neonatal measures it is likely to be in excess of 200 g/week. The studies are summarized in Table 1. The study was carefully designed, used a method for assessing maternal alcohol consumption with high testretest reliability;" and applied multiple regression techniques to control for the effects of confounding
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MATERNAL ALCOHOL AND CHILD DEVELOPMENT TABLE 1 Summary of sub-studies from the Seattle Pregnancy and Health Study First author
Date
Age
No.
Outcome variable
Comment
Alcohol measure''
Effects of alcohol consumption
MartinS LandesmanDwyer 3 Martin6
1977 1978
Neonate Neonate
305 124
learning behaviour
225 head turning, 80 sucking
E E&M
Streissguth"
1979 1983
Neonate Neonate
151 417
sucking habituation
Streissguth7
1980
8 months
462
BarrS Streissguth''
1984 1984
8 months 4 years
453 452
Streissguth 10
1989
4 years
421
mental and motor development infant size attention, reaction time Wechsler (WPPSI)
E 469 scheduled, missing data M due mainly to exclusion of 44 used for studying reliability E
poor newborn learning adverse effects on newborn behaviour decreased sucking pressure poor habituation, low arousal
Streissguth 11
1986
7 years
475
Streissguth l2, 14 Sampson 13
1989 1989
7 years
486
Streissguth 15
1990
7 years
482
E&M
attention, distraction, reaction time neurobehavioural battery
additional subjects added E from screening sample to keep sample size to about 500 a partial least squares analysis E&M (PLS) Multiple
IQ tests, learning problems, achievement scores
PLS
E&M Multiple
smaller infant size poor attention, slower reaction time decrement of 5 IQ points in children of mothers drinking ~250 g/week poor attention, distractibility, slower reaction time attention and memory deficits across both verbal and visual modalities, distractibility, poor organization, inflexible problem solving approach, arithmetic disabilities decrement of 7 IQ points when mother drinks ~ 165 g/week, reading difficulties, when mother drinks five drinks on at least one occasion
a E Early pregnancy (in the month or so prior to pregnancy recognition). M Midpregnancy, at about 22 weeks gestation. Multiple Many measures of alcohol consumption used. Both measures of alcohol consumption were used in the analyses, but in some publications only one is presented (A Streissguth, personal communication)
factors. However, a major potential bias exists in the way in which the subsamples were chosen but this cannot be evaluated from the published descriptions. OTHER STUDIES Effects of Maternal Alcohol Consumption on Neonatal Behaviour The relationship between maternal alcohol consumption during pregnancy and neonatal development has been investigated in many research centres other than Seattle. Ouellette and Rosett'? interviewed 200 women in Boston about their alcohol consumption during pregnancy. In contrast with the Seattle sample, most were black and poor. Frequency of hypotonia/jitteriness was found to increase with maternal alcohol consumption so that infants of moderate drinkers were more likely to exhibit these abnormalities than those of
abstainers but less likely than those of alcoholic women. The data analysis did not allow for the effects of confounding factors such as social class and smoking. In another American study, newborn behaviour was investigated in 173 infants of middle-class mothers. IS Multiple regression was used to control for confounding variables. Maternal antenatal alcohol consumption, obtained retrospectively after delivery, was related to greater placidity in infants three days after birth. This study is one of only a few in this literature in which retrospective consumption data were obtained, opening it to the serious objection of potential recall bias. The performance on the Brazelton Scale during the first three days of life was investigated by Coles et al. in 103 of 159 infants. 19 These healthy full-term infants
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E E
poor mental and motor development
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Effects ofAlcohol on Mental and Motor Development Several analyses have been published of data collected from subsamples at various ages of the 700 children in the Ottawa Prenatal Prospective Study. Gusella and Fried examined psychological development of 84
13-month old infants with the Bayley Scales.P' Maternal alcohol consumption during pregnancy was significantly, though not strongly, related to poorer mental development including poorer verbal comprehension and spoken language, but alcohol consumption before pregnancy was unrelated to mental development. Neither motor development nor behaviour was significantly associated with maternal alcohol consumption either before or after pregnancy. As only one woman drank as much as 250 g/week, the threshold for the observed effect was likely to be substantially lower than this. In a follow-up of 217 and 153 children aged 1 and 2 years respectively, there were no important relations at age 1 year between mothers' intake and the children's mental or physical development indices, but at 2 years there were significant associations with both the mental index and the Reynell comprehensive scores." This appeared to be related to an intake of at least 140 g/week. At age 3 years an association was found between maternal intake and the results of the Reynell but not the McCarthy test completed by about 133 children. At age 4 years these children's results were unrelated to pregnancy alcohol intake. As only four women drank more than three drinks a day, if there were a threshold, it would be below this, possibly between 100 and 150 g/week, though no data were presented to substantiate this. 26 Of the Seattle studies reviewed, three7 , l0 , 15 showed significant adverse effects of mothers' moderate drinking on children's mental and motor development. Other studies in this area do not support an association between moderate alcohol consumption during pregnancy and adverse effects on children's mental and motor development. In a study in Sweden, using a similar design to that of Coles et al. 19 the development of 22-month old children was compared using the Griffiths Scales," a test not unlike the Bayley. Three groups of mothers were defined: 40 controls who consumed less than 30 g/week in the month before their first antenatal clinic visit; 25 moderate drinkers who consumed between 30 g and 125 g/day (210-875 g/ week); and 15 alcoholic women who consumed more than 125 g/day (>875 g/week). Children of the alcoholic women had significantly poorer psychological development compared with controls, but there was no difference between children of moderate drinkers and of controls. A follow-up study of women in Cleveland Ohio investigated a number of developmental characteristics in up to 297 full-term children of an initial cohort of 359 seen at various times between ages 6 months and 4 years 10 months. The mothers, who were of predominantly lower social class, had been recruited
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were divided into three groups according to the drinking habits of their black, low social class mothers: those who abstained during pregnancy, those who drank throughout pregnancy (an average of 285 g/week), and those who drank but stopped by the second trimester. Multiple regression was used to examine the effect of confounding variables. Infants whose mothers continued to drink. throughout pregnancy were significantly lower in orientation, motor performance and autonomic regulation than non-exposed infants, but there was no difference between the children of abstainers and quitters. Thirtyone of the infants were tested again at 14 and 30 days of life. 20 Infants of mothers who had continued to drink were significantly lower in orientation, motor performance and autonomic regulation. Data from 81 infants showed that there was little evidence for a dose response over the range of consumption within a drinking group, except for the cluster scores of autonomic regulation and abnormal reflexes, which suggested a possible threshold at about 330 g/week." An early analysis from the Ottawa Prenatal Prospective Study examined the infant neurological development in a consecutively selected subsample of 59 children.P When the effects of smoking were controlled, maternal alcohol consumption was significantly related to decreased muscle tone at 9 days, but this effect had diminished by 30 days. Walpole and colleagues in Western Australia found no evidence of an effect of moderate consumption by 605 mothers on seven of eight behaviours measured using the Einstein Neonatal Behavioural Assessment Schedule." Allowance was made for a number of confounding variables including birthweight. The only marginally significant association was with tonus. As the highest of the three groups of alcohol consumption was equivalent to > 165 g/week, associations with the other behaviours might be expected only at levels rather higher than 165 g/week. The results of these studies appear to support the findings from the Seattle work on newborn infants, suggesting that maternal alcohol consumption during pregnancy is related to adverse effects on neonatal behaviour. The alcohol consumption levels at which effects tended to be observed were about 165 g/week or more. In general, the methodology was weak, small sample sizes were used and adjustments for the effects of confounding factors were not always made.
MATERNAL ALCOHOL AND CHILD DEVELOPMENT
a reflection of the truth, a pre-pregnancy intake threshold would be within the range 20-165 g/week. No relation between intake and body size was found.
Effects of Alcohol on Children's Behaviour Landesman-Dwyer et at." explored the relationship between maternal alcohol consumption during pregnancy and children's behaviour at 4 years of age. Two hundred and seventy-two subjects were selected for follow-up from 801 middle-class Seattle women on the basis of maternal alcohol and cigarette consumption. The behaviour of 128 children was observed in the home without knowledge of their mothers' alcohol consumption. After taking into account the effects of birth order, postnatal environment and smoking, it was concluded that children of moderate drinkers were less attentive, less compliant with parental commands and more fidgety than those of lighter drinkers. A possible threshold value in this study was 100 g/week. On the other hand, in the studies conducted in Ottawa.P' Stockholm?" and Dundee.P described in the previous section, no significant adverse effect on children's behaviour was found related to moderate maternal alcohol consumption during pregnancy. The weight of the evidence favours no relation between children's behaviour and pregnancy alcohol consumption. Alcohol and Infant Size A prospective study in Edinburgh, investigated whether birth abnormalities were related to maternal alcohol consumption;" The women were mostly not heavy drinkers. As part of this study, 835 infants were followed up at 3 months of age to assess their development. Maternal alcohol consumption was found to be significantly, though weakly, related to growth deficiency. The Seattle study" also suggested that moderate maternal alcohol consumption was related to retarded growth, although with diminishing strength as the children grew older. On the other hand, no significant effect on children's growth was observed in either the small Stockholm-? or large Dundee (unpublished) studies. As there have been few studies of growth related to moderate alcohol consumption during pregnancy, the evidence so far is inconclusive. CONCLUSIONS An overview of the results for drinking during pregnancy is given in Table 2. The majority of the samples sizes were small « 2(0), although in some stratification may have strengthened the designs. Only the Seattle, Edinburgh and Dundee studies included substantial numbers. Because of the variety of outcomes and the manifold methods for evaluating
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over a 15-month period. They were screened using the Michigan Alcoholism Screening Test (MAST).28 Those who scored 5 or over were matched with women scoring less than 5 on a number of demographic and subtance use variables. Measures of alcohol consumption included the MAST score, two assessments of average daily intake during pregnancy, one derived from responses during pregnancy and the other from responses when the child was 4 years 10 months. A tally of craniofacial abnormalities was also used as a proxy for maternal alcohol consumption. The children were tested for language development," attention sparr'? and cognitive development." With the exception of the one child diagnosed as having FAS, there was no evidence that any of the developmental measures were related to maternal alcohol consumption during pregnancy. As no data were given about the levels of consumption, a level below which no effect was observed could not be derived. However, it is likely to be above three drinks a day (200 g/week absolute alcohol) as the women with MAST scores ~5 were identified as alcoholic. Some of the results of the UK component of the EUROMAC study have been reported in a separate publication;" Child assessments using the Bayley Scales were performed blind to knowledge of maternal alcohol consumption. Multiple regression analyses of the data for all 592 children, for 559 full-term children; and for 535 full-term children who did not enter the Special Care Baby Unit showed no significant adverse effect of maternal alcohol consumption before, during or after pregnancy on children's mental and motor development after controlling for the effects of smoking, social class, sex, birthweight and gestational age. The highest intake was 440 g/week, but almost all the women in the ~ 100 g group drank less than 200 g/ week absolute alcohol. In a small study of only 60 infants, Coles et al. 20 reassessed a sub-sample from their neonatal study (described above) at 6 months of age and found no difference in Bayley Scale mental and motor performance between children of mothers consuming different levels of alcohol during pregnancy. The sample size was small and the authors did not specify how the children were selected for follow-up. O'Connor and co-workers" applied the Bayley Scales to 25 1 year old infants of white, highly educated mothers aged 30 or more who were asked retrospectively about peripregnancy drinking. There was a highly significant negative correlation between the mental index values and pre-pregnancy drinking, but there was no relation at all with drinking during pregnancy. The sample was so small the positive result may simply have been a rare chance occurrence, but if
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY (SUPPLEMENT 1) TABLE 2
Summary offindings from studies on moderate alcohol consumption during pregnancy and child development Date
No.
Neonatal behavioural problems
Martins Martin 6 Landesman-Dwyerf Streissguthf Ouellette17
1977 1979 1978 1983 1976 1983 1984 1985 1986 1987 1991 1980 1981 1984 1984 1984 1985 1986 1986 1987 1987 1988 1988 1989 1989 1990 1990 1990 1991 1991 1991 1991
305 151 124 417 200 59 173 103 149 31 605 462 128 453 452 84 80 475 25 601 103 217 153 421 486 482
.J .J .J .J .J .J .J .J .J .J x
Staisey22 Jacobson l 8 Coles l6 Smith21 Coles 20 Walpole23 Streissguth7 Landesman-Dwyerf ' Barr8 Streissguth/ Gusella24 Larsson27
Streissguth II O'Connor32 Plant35 Coles20 Fried (lyr old)25 Fried (2yr old)25 Streissguth 10 Streissguth14 Streissguth l5 Fried (3yr old)26 Fried (4yr old)26 Forrest 28 Greene 31 Greene (language)29 Boyd 30
.J: x:
Poorer mental development
Poorer motor development
Behavioural problems in children
Smaller infant size
.J .J x x x
x x
133
.J .J .J .J .J
130 592 297 279 245
x x x x x
x x
x
x .J
x .J
x x x x x
x x x
x
x
x
x
A significant relation with maternal alcohol consumption. No significant relation reported. Not applicable.
alcohol consumption, there is no way in which the data from the studies can be combined in a meta-analysis. Table 2 gives a visual impression of the frequency of positive findings and more weight might be given to the larger studies. Neonatal problems seem universally to be observed. The lowest potential threshold value for an effect of alcohol was about 165 g/week in these studies. For child development beyond the neonatal stage, the evidence for adverse effects is less convincing. The balance of evidence is heavily weighted towards no effect, but the positive and relatively large Seattle study suggests that consumption over 150 g/week may be harmful to children's mental and motor development. Three studies, two within the Pregnancy and Health Study9,11 and the third also carried out in Seattle ,34
suggested that moderate maternal alcohol consumption during pregnancy was associated with adverse behavioural effects, but other studies in three separate countries showed no evidence of such an effect. 24,27,32 More weight might be given to the negative studies since they were carried out in different geographical locations whereas all the studies with positive findings were on subjects drawn from the same population. Two studies showed that moderate drinking was related to smaller infant size 8 ,36 but three studies found no effect. 27,33,35 The Seattle study suggested an effect at 160 g/week." Maternal alcoholism during pregnancy may have long-lasting implications for the development of the child. Whether or not moderate consumption during pregnancy affects child development remains an
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First author
MATERNAL ALCOHOL AND CHILD DEVELOPMENT
unresolved problem. At present the lowest levels of consumption that can be associated with altered child development seem to be above 150 g/week, and do not appear to be lower than observed for the immediate outcome of pregnancy. REFERENCES
Ouellette E M, Rosett H L. A pilot prospective study of the fetal alcohol syndrome at the Boston City Hospital. Part II: The infants. Ann NY A cad Sci 1976; 273: 123-29. 18 Jacobson S W, Fein G G, Jacobson J L, Schwartz P M, Dowler J K. Neonatal correlates of prenatal exposure to smoking, caffeine, and alcohol. Inf Behav Dev 1984; 7: 253-65. 19 Coles C D, Smith I, Fernhoff P M, Falek A. Neonatal neurobehavioral characteristics as correlates of maternal alcohol use during gestation. Alcohol Clin Exp Res 1985; 9: 454-60. 20 Coles C D, Smith IE, Falek A. Prenatal alcohol exposure and infant behavior: Immediate effects and implications for later development. Ady Alcohol Subst Abuse 1987; 6: 87-104. 21 Smith I E, Coles C D, Lancaster J, Fernhoff PM, Falek A. The effect of volume and duration of prenatal ethanol exposure on neonatal physical and behavioral development. Neurobehav Toxicol Teratol1986; 8: 375-81. 22 Staisey N L, Fried P A. Relationships between moderate maternal alcohol consumption during pregnancy and infant neurological development. J Stud Alcohol 1983; 44: 262-70. 23 Walpole I, Zubrick S, Pontre J, Lawrence C. Low to moderate maternal alcohol use before and during pregnancy and neurobehavioural outcome in the newborn infant. Dey Med Child Neurology 1991; 33: 875-83. 24 Gusella J L, Fried P A. Effects of maternal social drinking and smoking on offspring at 13 months. Neurobehav Toxicol Teratol1984; 6: 13-17. 25 Fried P A, Watkinson B. 12- and 24-month neurobehavioural follow-up of children prenatally exposed to marihuana, cigarettes and alcohol. Neurotoxicol Teratol1988; 10: 305-13. 26 Fried P A, Watkinson B. 36- and 48-month neurobehavioral follow-up of children prenatally exposed to marijuana, cigarettes and alcohol. J Dev Behav Pediatr 1990; 11: 49-58. 27 Larsson G, Bohlin A-B, Tunell R. Prospective study of children exposed to variable amounts of alcohol in utero. Arch Dis Child 1985; 60: 316-21. 28 Selzer M L. The Michigan Alcoholism Screening Test: The quest for a new diagnostic instrument. Am J Psychiatry 1971; 127: 1653-58. 29 Greene T, Ernhart C B, Martier S, Sokol R, Ager J. Prenatal alcohol exposure and language development. Alcohol Clin Exp Res 1991; 14: 937-45. 30 Boyd T A, Emhart C B, Greene T H, Sokol R J, Martier S. Prenatal alcohol exposure and sustained attention in the preschool years. Neurotoxicol Teratol1991; 13: 49-55. 31 Greene T, Ernhart C B, Ager J, Sokol R, Martier S, Boyd T. Prenatal alcohol exposure and cognitive development in the preschool years. Neurotoxicol Teratol1991; 13: 57-68. 32 Forrest F M, Florey C du V, Taylor D J, McPherson F, Young J A. Reported social alcohol consumption during pregnancy and infants' development at 18 months. Br Med J 1991; 303: 22-26. 33 O'Connor M J, Brill N J, Sigman M. Alcohol use in primiparous women older than 30 years of age: Relation to infant development. Pediatrics 1986; 78: 444-50. 34 Landesman-Dwyer S, Ragozin A S, Little R E. Behavioural correlates of prenatal alcohol exposure: A four-year follow-up study. Neurobehav Toxicol Teratol1981; 3: 187-93. 35 Forrest F M L. The relation between infant psychological development and maternal alcohol consumption during pregnancy. [PhD thesis]. Dundee (Scotland): University of Dundee, 1991. 36 Plant M. Women, drinking and pregnancy. London: Tavistock Publications, 1987. 17
Downloaded from http://ije.oxfordjournals.org/ by guest on August 17, 2015
Forrest F, Florey C du V. The relation between maternal alcohol consumption and child development. The epidemiological evidence. J Public Health Med 1991; 13: 247-55. 2 Streissguth A P, Martin D C, Martin J C, Barr H M. The Seattle longitudinal prospective study on alcohol and pregnancy. Neurobehav Toxicol Teratol1981; 3: 223-33. 3 Landesman-Dwyer S, Keller L S, Streissguth A P. Naturalistic observations of newborns: Effects of maternal alcohol intake. Alcohol Clin Exp Res 1978; 2: 171-77. 4 Streissguth A P, Barr H M, Martin DC. Maternal alcohol use and neonatal habituation assessed with the Brazelton Scale. Child Dey 1983; 54: 1109-18. 5 Martin J, Martin D C, Lund C A, Streissguth A P. Maternal alcohol ingestion and cigarette smoking and their effects on newborn conditioning. Alcohol Clin Exp Res 1977; 1: 243-47. 6 Martin D C, Martin J C, Streissguth A P, Lund C A. Sucking frequency and amplitude in newborns as a function of maternal drinking and smoking. In: Currents in Alcoholism Vol V. Galanter M (ed.) New York: Grune and Stratton, 1979; pp. 359-66. 7 Streissguth A P, Barr H M, Martin D C, Herman C S. Effects of maternal alcohol, nicotine, and caffeine use during pregnancy on infant and motor development at eight months. Alcohol Clin Exp Res 1980; 4: 152-64. 8 Barr H M, Streissguth A P, Martin DC, Herman C S. Infant size at 8 months of age: Relationship to maternal use of alcohol, nicotine, and caffeine during pregnancy. Pediatrics 1984; 74: 336-41. 9 Streissguth A P, Martin D C, Barr H M, Sandman B MacG. Intrauterine alcohol and nicotine exposure: Attention and reaction time in 4-year-old children. Dey PsychoI1984; 20: 533-41. 10 Streissguth A P, Barr H M, Sampson P D, Darby B L, Martin D C. IQ at age 4 in relation to maternal alcohol use and smoking during pregnancy. Dey Psychol1989; 25: 3-11. 11 Streissguth A P, Barr H M, Sampson P D, Parrish-Johnson J C, Kirchner G L, Martin D C. Attention, distraction and reaction time at age 7 years and prenatal alcohol exposure. Neurobehav Toxicol Teratol 1986; 8: 717-25. 12 Streissguth A P, Barr H M, Sampson P D, Bookstein F L, Darby B L. Neurobehavioral effects of prenatal alcohol: Part 1. Research strategy. Neurotoxicol Teratol1989; 11: 461-76. 13 Sampson P D, Streissguth A P, Barr H M, Bookstein F L. Neurobehavioral effects of prenatal alcohol: Part II. Partial least squares analysis. Neurotoxicol Teratol1989; 11: 477-91. 14 Streissguth A P, Sampson P D, Bookstein F L, Barr H M. Neurobehavioral effects of prenatal alcohol: Part III. PLS analyses of neuropsychologic tests. Neurotoxicol Teratol1989; 11: 493-507. 15 Streissguth A P, Barr H M, Sampson P D. Moderate prenatal alcohol exposure: effects on child IQ and learning problems at age 7Y2 years. Alcohol Clin Exp Res 1990; 14: 662-69. 16 Streissguth A P, Martin D C, Buffington V E. Test-retest reliability of three scales derived from a quantity-frequency-variability assessment of self-reported alcohol consumption. Ann NY Acad Sci 1976; 273: 458-66. I
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International Journal of Epidemiology © International Epidemiological Association 1992
Chapter 3 Maternal Alcohol Consumption and Child Development F FORREST, C DU V FLOREY AND D TAYLOR
INTRODUCTION In the previous chapter the evidence of a relation between alcohol consumption during pregnancy and the immediate outcome of pregnancy was reviewed. It was concluded that although adverse outcomes were regularly seen at consumption levels of two or more drinks a day (about 140 g/week absolute alcohol). below this level results were inconsistent. In this chapter we ask whether this is also the case for child development. The term 'moderate alcohol consumption' has been used loosely here to mean levels of drinking that would be socially acceptable. but does not carry any specific connotation of quantity. The studies of child development have been based on the hypothesis that the offspring of moderate to heavy drinkers would have similar qualitative deficits to those seen in studies of the newborn and the central nervous system deficits of the fetal alcohol syndrome (FAS). Authors have considered a variety of outcome measures including behaviour. mental and physical development, and learning ability. We have reviewed the types of outcome measure related to alcohol consumption and have attempted to find an approximate level of intake which is usually associated with adverse outcome. We have drawn on a previous review! for the 'threshold' values suggested below.
born between February 1975 and March 1976 to white, married, middle-class women selected from a consecutive sample of 1529 pregnant women. The cohort was selected before delivery to include 250 of the heavier drinkers and smokers and 250 of the light drinkers and abstainers. Those who conducted the infant assessments were not involved in the sample selection. The sample size varied between sub studies due to their different lengths and timings, the number of eligible infants delivered during the period of each substudy, the number of hospitals at which the substudies were conducted and factors such as examiner illness and equipment failure. The subsamples were not randomly chosen from the screening sample but it was not made explicit how the samples were chosen. Furthermore. the initial cohort of 500 children could not be maintained over the duration of the study so others in the original 1529 who were available at the time were recruited to make up the numbers. Quantity, frequency and variability of alcohol consumption were obtained by a single interview with the mother in the fifth month of pregnancy. She was asked about drinking in two time periods: in the month or so prior to recognition of pregnancy (termed early pregnancy in the publications) and around the time of interview, or mid pregnancy. The early pregnancy values were considered to represent prepregnancy behaviour on the assumption that the drinking pattern would not alter until after recognition of pregnancy (A Streissguth, personal communication). Consumption was quantified using average ounces of absolute alcohol consumed per day. Multiple regression analysis was used to control for the effects of
THE SEATTLE PREGNANCY AND HEALTH STUDY Streissguth et al.? initiated the earliest and longest follow-up study on the effects of moderate alcohol consumption. The Pregnancy and Health Study sample consisted of a follow-up cohort of 500 children S17
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Studies of development and behaviour from shortly after birth up to the age of 7 years are reviewed. Maternal alcohol consumption above 150-200 g/week is related to behaviour in many studies, but below this level there is little epidemiological evidence of association. There is no evidence that the levels of consumption associated with adverse behaviour are lower than those associated with adverse pregnancy outcome.
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY (SUPPLEMENT 1)
potentially confounding variables including smoking, caffeine, drugs, diet, obstetric history and demographic characteristics. Maternal alcohol consumption and its relation to child development was studied at three different stages of development: infancy, during the preschool years, and at 7 years of age. All outcome measures were conducted blind to knowledge of maternal alcohol consumption.
Infant and Child Development Studies Mental and motor development at 8 months were examined in 462 infants? using the Bayley Scales of Infant Development. The children's developmental indices were significantly lower if their mothers had consumed 165 g/week or more in early pregnancy, after controlling for confounding variables. Body size was measured at 8 months in 453 of these infants." After
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Newborn Behaviour Newborn behaviour, habituation, learning and sucking pressure were analysed for their relation to maternal alcohol consumption in both periods for which data were collected. On the first day of life, behaviour was measured using the Brazelton Neonatal Assessment Scale in 124 infants, selected according to level of maternal alcohol consumption." Alcohol consumption grouped according to consumption in both early and mid pregnancy was significantly related to five of 16 behaviours and to the proportion of time infants tremored, positioned their head to the left, had their eyes open, touched their hands to their face and decreased the amount of vigorous body activity. Habituation, also assessed by the Brazelton Scale, was investigated in 417 infants." Drinking in mid pregnancy was significantly related to two (poor habituation and low arousal) of six dependent factors after adjusting for confounding factors. Learning and sucking pressure were measured on the second day of life. Learning was investigated using a head-turning conditioning task with 225 infants and a sucking task with 80 infants.! Moderate alcohol consumption in early pregnancy and moderate to heavy cigarette consumption had an interactive adverse effect on the infants' performance. Sucking pressure was electronically recorded in 151 infants." After control for the effects of possible confounding variables, heavier maternal alcohol consumption during early pregnancy was significantly related to decreased pressure. The effects were associated with levels of maternal alcohol intake of 10z absolute alcohol!day or more (~165 g/week) in those papers which presented data for women in different consumption categories. I
adjusting for the effects of confounding variables, maternal alcohol consumption in early pregnancy at possibly 160 g/week was related to lower infant weight and length and less strongly associated with smaller head circumference. The relation between alcohol consumption and infant size was weaker at 8 months than at birth. Attention and reaction time was investigated in 452 four year olds using a computer-controlled vigilance task.? Heavier maternal alcohol use in early pregnancy was significantly related to poorer attention and increased reaction time but not to activity, after adjusting for controlling factors. A second analysis of four year olds reported results from testing 421 children with the Wechsler scales. The mean IQ was 5 points lower in children whose mothers drank more than 250 g/week in early pregnancy than in children of mothers who drank less. 10 The continuing adverse effects of maternal alcohol consumption on attention and reaction time was demonstrated in 475 seven year olds (6.5-8.5 years).!' The sample size was larger than at the four-year follow-up since additional subjects were added to the cohort from the original screening sample to keep the sample size at around 500. Alcohol consumption during early pregnancy was significantly associated with attentional deficits and slower reaction time, but was unrelated to time spent in motion. Ratings of distraction were related to alcohol consumption of ~250 g/week. A more sophisticated analysis of 158 outcomes, with many covariates, confirmed these findings, but did not allow the identification of a potential threshold value for alcohol consumption. 12,13,14 A further analysis revealed that mothers drinking ~ 165 g/week in mid pregnancy had children who on average had a deficit of 7 IQ points and children of mothers drinking five drinks or more on any occasion (binge drinking) had learning problems significantly more often than those whose mothers drank less." Findings from the Seattle Pregnancy and Health Study indicate that maternal alcohol consumption during pregnancy is related to neonatal behavioural problems, poorer infant mental and motor development, smaller infant size and behavioural problems in preschool and school-age children. In as far as the data in the papers allow identification of a possible threshold for alcohol consumption, the lowest is about 160 g/week for growth but for the mental and neonatal measures it is likely to be in excess of 200 g/week. The studies are summarized in Table 1. The study was carefully designed, used a method for assessing maternal alcohol consumption with high testretest reliability;" and applied multiple regression techniques to control for the effects of confounding
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MATERNAL ALCOHOL AND CHILD DEVELOPMENT TABLE 1 Summary of sub-studies from the Seattle Pregnancy and Health Study First author
Date
Age
No.
Outcome variable
Comment
Alcohol measure''
Effects of alcohol consumption
MartinS LandesmanDwyer 3 Martin6
1977 1978
Neonate Neonate
305 124
learning behaviour
225 head turning, 80 sucking
E E&M
Streissguth"
1979 1983
Neonate Neonate
151 417
sucking habituation
Streissguth7
1980
8 months
462
BarrS Streissguth''
1984 1984
8 months 4 years
453 452
Streissguth 10
1989
4 years
421
mental and motor development infant size attention, reaction time Wechsler (WPPSI)
E 469 scheduled, missing data M due mainly to exclusion of 44 used for studying reliability E
poor newborn learning adverse effects on newborn behaviour decreased sucking pressure poor habituation, low arousal
Streissguth 11
1986
7 years
475
Streissguth l2, 14 Sampson 13
1989 1989
7 years
486
Streissguth 15
1990
7 years
482
E&M
attention, distraction, reaction time neurobehavioural battery
additional subjects added E from screening sample to keep sample size to about 500 a partial least squares analysis E&M (PLS) Multiple
IQ tests, learning problems, achievement scores
PLS
E&M Multiple
smaller infant size poor attention, slower reaction time decrement of 5 IQ points in children of mothers drinking ~250 g/week poor attention, distractibility, slower reaction time attention and memory deficits across both verbal and visual modalities, distractibility, poor organization, inflexible problem solving approach, arithmetic disabilities decrement of 7 IQ points when mother drinks ~ 165 g/week, reading difficulties, when mother drinks five drinks on at least one occasion
a E Early pregnancy (in the month or so prior to pregnancy recognition). M Midpregnancy, at about 22 weeks gestation. Multiple Many measures of alcohol consumption used. Both measures of alcohol consumption were used in the analyses, but in some publications only one is presented (A Streissguth, personal communication)
factors. However, a major potential bias exists in the way in which the subsamples were chosen but this cannot be evaluated from the published descriptions. OTHER STUDIES Effects of Maternal Alcohol Consumption on Neonatal Behaviour The relationship between maternal alcohol consumption during pregnancy and neonatal development has been investigated in many research centres other than Seattle. Ouellette and Rosett'? interviewed 200 women in Boston about their alcohol consumption during pregnancy. In contrast with the Seattle sample, most were black and poor. Frequency of hypotonia/jitteriness was found to increase with maternal alcohol consumption so that infants of moderate drinkers were more likely to exhibit these abnormalities than those of
abstainers but less likely than those of alcoholic women. The data analysis did not allow for the effects of confounding factors such as social class and smoking. In another American study, newborn behaviour was investigated in 173 infants of middle-class mothers. IS Multiple regression was used to control for confounding variables. Maternal antenatal alcohol consumption, obtained retrospectively after delivery, was related to greater placidity in infants three days after birth. This study is one of only a few in this literature in which retrospective consumption data were obtained, opening it to the serious objection of potential recall bias. The performance on the Brazelton Scale during the first three days of life was investigated by Coles et al. in 103 of 159 infants. 19 These healthy full-term infants
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E E
poor mental and motor development
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY (SUPPLEMENT 1)
Effects ofAlcohol on Mental and Motor Development Several analyses have been published of data collected from subsamples at various ages of the 700 children in the Ottawa Prenatal Prospective Study. Gusella and Fried examined psychological development of 84
13-month old infants with the Bayley Scales.P' Maternal alcohol consumption during pregnancy was significantly, though not strongly, related to poorer mental development including poorer verbal comprehension and spoken language, but alcohol consumption before pregnancy was unrelated to mental development. Neither motor development nor behaviour was significantly associated with maternal alcohol consumption either before or after pregnancy. As only one woman drank as much as 250 g/week, the threshold for the observed effect was likely to be substantially lower than this. In a follow-up of 217 and 153 children aged 1 and 2 years respectively, there were no important relations at age 1 year between mothers' intake and the children's mental or physical development indices, but at 2 years there were significant associations with both the mental index and the Reynell comprehensive scores." This appeared to be related to an intake of at least 140 g/week. At age 3 years an association was found between maternal intake and the results of the Reynell but not the McCarthy test completed by about 133 children. At age 4 years these children's results were unrelated to pregnancy alcohol intake. As only four women drank more than three drinks a day, if there were a threshold, it would be below this, possibly between 100 and 150 g/week, though no data were presented to substantiate this. 26 Of the Seattle studies reviewed, three7 , l0 , 15 showed significant adverse effects of mothers' moderate drinking on children's mental and motor development. Other studies in this area do not support an association between moderate alcohol consumption during pregnancy and adverse effects on children's mental and motor development. In a study in Sweden, using a similar design to that of Coles et al. 19 the development of 22-month old children was compared using the Griffiths Scales," a test not unlike the Bayley. Three groups of mothers were defined: 40 controls who consumed less than 30 g/week in the month before their first antenatal clinic visit; 25 moderate drinkers who consumed between 30 g and 125 g/day (210-875 g/ week); and 15 alcoholic women who consumed more than 125 g/day (>875 g/week). Children of the alcoholic women had significantly poorer psychological development compared with controls, but there was no difference between children of moderate drinkers and of controls. A follow-up study of women in Cleveland Ohio investigated a number of developmental characteristics in up to 297 full-term children of an initial cohort of 359 seen at various times between ages 6 months and 4 years 10 months. The mothers, who were of predominantly lower social class, had been recruited
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were divided into three groups according to the drinking habits of their black, low social class mothers: those who abstained during pregnancy, those who drank throughout pregnancy (an average of 285 g/week), and those who drank but stopped by the second trimester. Multiple regression was used to examine the effect of confounding variables. Infants whose mothers continued to drink. throughout pregnancy were significantly lower in orientation, motor performance and autonomic regulation than non-exposed infants, but there was no difference between the children of abstainers and quitters. Thirtyone of the infants were tested again at 14 and 30 days of life. 20 Infants of mothers who had continued to drink were significantly lower in orientation, motor performance and autonomic regulation. Data from 81 infants showed that there was little evidence for a dose response over the range of consumption within a drinking group, except for the cluster scores of autonomic regulation and abnormal reflexes, which suggested a possible threshold at about 330 g/week." An early analysis from the Ottawa Prenatal Prospective Study examined the infant neurological development in a consecutively selected subsample of 59 children.P When the effects of smoking were controlled, maternal alcohol consumption was significantly related to decreased muscle tone at 9 days, but this effect had diminished by 30 days. Walpole and colleagues in Western Australia found no evidence of an effect of moderate consumption by 605 mothers on seven of eight behaviours measured using the Einstein Neonatal Behavioural Assessment Schedule." Allowance was made for a number of confounding variables including birthweight. The only marginally significant association was with tonus. As the highest of the three groups of alcohol consumption was equivalent to > 165 g/week, associations with the other behaviours might be expected only at levels rather higher than 165 g/week. The results of these studies appear to support the findings from the Seattle work on newborn infants, suggesting that maternal alcohol consumption during pregnancy is related to adverse effects on neonatal behaviour. The alcohol consumption levels at which effects tended to be observed were about 165 g/week or more. In general, the methodology was weak, small sample sizes were used and adjustments for the effects of confounding factors were not always made.
MATERNAL ALCOHOL AND CHILD DEVELOPMENT
a reflection of the truth, a pre-pregnancy intake threshold would be within the range 20-165 g/week. No relation between intake and body size was found.
Effects of Alcohol on Children's Behaviour Landesman-Dwyer et at." explored the relationship between maternal alcohol consumption during pregnancy and children's behaviour at 4 years of age. Two hundred and seventy-two subjects were selected for follow-up from 801 middle-class Seattle women on the basis of maternal alcohol and cigarette consumption. The behaviour of 128 children was observed in the home without knowledge of their mothers' alcohol consumption. After taking into account the effects of birth order, postnatal environment and smoking, it was concluded that children of moderate drinkers were less attentive, less compliant with parental commands and more fidgety than those of lighter drinkers. A possible threshold value in this study was 100 g/week. On the other hand, in the studies conducted in Ottawa.P' Stockholm?" and Dundee.P described in the previous section, no significant adverse effect on children's behaviour was found related to moderate maternal alcohol consumption during pregnancy. The weight of the evidence favours no relation between children's behaviour and pregnancy alcohol consumption. Alcohol and Infant Size A prospective study in Edinburgh, investigated whether birth abnormalities were related to maternal alcohol consumption;" The women were mostly not heavy drinkers. As part of this study, 835 infants were followed up at 3 months of age to assess their development. Maternal alcohol consumption was found to be significantly, though weakly, related to growth deficiency. The Seattle study" also suggested that moderate maternal alcohol consumption was related to retarded growth, although with diminishing strength as the children grew older. On the other hand, no significant effect on children's growth was observed in either the small Stockholm-? or large Dundee (unpublished) studies. As there have been few studies of growth related to moderate alcohol consumption during pregnancy, the evidence so far is inconclusive. CONCLUSIONS An overview of the results for drinking during pregnancy is given in Table 2. The majority of the samples sizes were small « 2(0), although in some stratification may have strengthened the designs. Only the Seattle, Edinburgh and Dundee studies included substantial numbers. Because of the variety of outcomes and the manifold methods for evaluating
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over a 15-month period. They were screened using the Michigan Alcoholism Screening Test (MAST).28 Those who scored 5 or over were matched with women scoring less than 5 on a number of demographic and subtance use variables. Measures of alcohol consumption included the MAST score, two assessments of average daily intake during pregnancy, one derived from responses during pregnancy and the other from responses when the child was 4 years 10 months. A tally of craniofacial abnormalities was also used as a proxy for maternal alcohol consumption. The children were tested for language development," attention sparr'? and cognitive development." With the exception of the one child diagnosed as having FAS, there was no evidence that any of the developmental measures were related to maternal alcohol consumption during pregnancy. As no data were given about the levels of consumption, a level below which no effect was observed could not be derived. However, it is likely to be above three drinks a day (200 g/week absolute alcohol) as the women with MAST scores ~5 were identified as alcoholic. Some of the results of the UK component of the EUROMAC study have been reported in a separate publication;" Child assessments using the Bayley Scales were performed blind to knowledge of maternal alcohol consumption. Multiple regression analyses of the data for all 592 children, for 559 full-term children; and for 535 full-term children who did not enter the Special Care Baby Unit showed no significant adverse effect of maternal alcohol consumption before, during or after pregnancy on children's mental and motor development after controlling for the effects of smoking, social class, sex, birthweight and gestational age. The highest intake was 440 g/week, but almost all the women in the ~ 100 g group drank less than 200 g/ week absolute alcohol. In a small study of only 60 infants, Coles et al. 20 reassessed a sub-sample from their neonatal study (described above) at 6 months of age and found no difference in Bayley Scale mental and motor performance between children of mothers consuming different levels of alcohol during pregnancy. The sample size was small and the authors did not specify how the children were selected for follow-up. O'Connor and co-workers" applied the Bayley Scales to 25 1 year old infants of white, highly educated mothers aged 30 or more who were asked retrospectively about peripregnancy drinking. There was a highly significant negative correlation between the mental index values and pre-pregnancy drinking, but there was no relation at all with drinking during pregnancy. The sample was so small the positive result may simply have been a rare chance occurrence, but if
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY (SUPPLEMENT 1) TABLE 2
Summary offindings from studies on moderate alcohol consumption during pregnancy and child development Date
No.
Neonatal behavioural problems
Martins Martin 6 Landesman-Dwyerf Streissguthf Ouellette17
1977 1979 1978 1983 1976 1983 1984 1985 1986 1987 1991 1980 1981 1984 1984 1984 1985 1986 1986 1987 1987 1988 1988 1989 1989 1990 1990 1990 1991 1991 1991 1991
305 151 124 417 200 59 173 103 149 31 605 462 128 453 452 84 80 475 25 601 103 217 153 421 486 482
.J .J .J .J .J .J .J .J .J .J x
Staisey22 Jacobson l 8 Coles l6 Smith21 Coles 20 Walpole23 Streissguth7 Landesman-Dwyerf ' Barr8 Streissguth/ Gusella24 Larsson27
Streissguth II O'Connor32 Plant35 Coles20 Fried (lyr old)25 Fried (2yr old)25 Streissguth 10 Streissguth14 Streissguth l5 Fried (3yr old)26 Fried (4yr old)26 Forrest 28 Greene 31 Greene (language)29 Boyd 30
.J: x:
Poorer mental development
Poorer motor development
Behavioural problems in children
Smaller infant size
.J .J x x x
x x
133
.J .J .J .J .J
130 592 297 279 245
x x x x x
x x
x
x .J
x .J
x x x x x
x x x
x
x
x
x
A significant relation with maternal alcohol consumption. No significant relation reported. Not applicable.
alcohol consumption, there is no way in which the data from the studies can be combined in a meta-analysis. Table 2 gives a visual impression of the frequency of positive findings and more weight might be given to the larger studies. Neonatal problems seem universally to be observed. The lowest potential threshold value for an effect of alcohol was about 165 g/week in these studies. For child development beyond the neonatal stage, the evidence for adverse effects is less convincing. The balance of evidence is heavily weighted towards no effect, but the positive and relatively large Seattle study suggests that consumption over 150 g/week may be harmful to children's mental and motor development. Three studies, two within the Pregnancy and Health Study9,11 and the third also carried out in Seattle ,34
suggested that moderate maternal alcohol consumption during pregnancy was associated with adverse behavioural effects, but other studies in three separate countries showed no evidence of such an effect. 24,27,32 More weight might be given to the negative studies since they were carried out in different geographical locations whereas all the studies with positive findings were on subjects drawn from the same population. Two studies showed that moderate drinking was related to smaller infant size 8 ,36 but three studies found no effect. 27,33,35 The Seattle study suggested an effect at 160 g/week." Maternal alcoholism during pregnancy may have long-lasting implications for the development of the child. Whether or not moderate consumption during pregnancy affects child development remains an
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First author
MATERNAL ALCOHOL AND CHILD DEVELOPMENT
unresolved problem. At present the lowest levels of consumption that can be associated with altered child development seem to be above 150 g/week, and do not appear to be lower than observed for the immediate outcome of pregnancy. REFERENCES
Ouellette E M, Rosett H L. A pilot prospective study of the fetal alcohol syndrome at the Boston City Hospital. Part II: The infants. Ann NY A cad Sci 1976; 273: 123-29. 18 Jacobson S W, Fein G G, Jacobson J L, Schwartz P M, Dowler J K. Neonatal correlates of prenatal exposure to smoking, caffeine, and alcohol. Inf Behav Dev 1984; 7: 253-65. 19 Coles C D, Smith I, Fernhoff P M, Falek A. Neonatal neurobehavioral characteristics as correlates of maternal alcohol use during gestation. Alcohol Clin Exp Res 1985; 9: 454-60. 20 Coles C D, Smith IE, Falek A. Prenatal alcohol exposure and infant behavior: Immediate effects and implications for later development. Ady Alcohol Subst Abuse 1987; 6: 87-104. 21 Smith I E, Coles C D, Lancaster J, Fernhoff PM, Falek A. The effect of volume and duration of prenatal ethanol exposure on neonatal physical and behavioral development. Neurobehav Toxicol Teratol1986; 8: 375-81. 22 Staisey N L, Fried P A. Relationships between moderate maternal alcohol consumption during pregnancy and infant neurological development. J Stud Alcohol 1983; 44: 262-70. 23 Walpole I, Zubrick S, Pontre J, Lawrence C. Low to moderate maternal alcohol use before and during pregnancy and neurobehavioural outcome in the newborn infant. Dey Med Child Neurology 1991; 33: 875-83. 24 Gusella J L, Fried P A. Effects of maternal social drinking and smoking on offspring at 13 months. Neurobehav Toxicol Teratol1984; 6: 13-17. 25 Fried P A, Watkinson B. 12- and 24-month neurobehavioural follow-up of children prenatally exposed to marihuana, cigarettes and alcohol. Neurotoxicol Teratol1988; 10: 305-13. 26 Fried P A, Watkinson B. 36- and 48-month neurobehavioral follow-up of children prenatally exposed to marijuana, cigarettes and alcohol. J Dev Behav Pediatr 1990; 11: 49-58. 27 Larsson G, Bohlin A-B, Tunell R. Prospective study of children exposed to variable amounts of alcohol in utero. Arch Dis Child 1985; 60: 316-21. 28 Selzer M L. The Michigan Alcoholism Screening Test: The quest for a new diagnostic instrument. Am J Psychiatry 1971; 127: 1653-58. 29 Greene T, Ernhart C B, Martier S, Sokol R, Ager J. Prenatal alcohol exposure and language development. Alcohol Clin Exp Res 1991; 14: 937-45. 30 Boyd T A, Emhart C B, Greene T H, Sokol R J, Martier S. Prenatal alcohol exposure and sustained attention in the preschool years. Neurotoxicol Teratol1991; 13: 49-55. 31 Greene T, Ernhart C B, Ager J, Sokol R, Martier S, Boyd T. Prenatal alcohol exposure and cognitive development in the preschool years. Neurotoxicol Teratol1991; 13: 57-68. 32 Forrest F M, Florey C du V, Taylor D J, McPherson F, Young J A. Reported social alcohol consumption during pregnancy and infants' development at 18 months. Br Med J 1991; 303: 22-26. 33 O'Connor M J, Brill N J, Sigman M. Alcohol use in primiparous women older than 30 years of age: Relation to infant development. Pediatrics 1986; 78: 444-50. 34 Landesman-Dwyer S, Ragozin A S, Little R E. Behavioural correlates of prenatal alcohol exposure: A four-year follow-up study. Neurobehav Toxicol Teratol1981; 3: 187-93. 35 Forrest F M L. The relation between infant psychological development and maternal alcohol consumption during pregnancy. [PhD thesis]. Dundee (Scotland): University of Dundee, 1991. 36 Plant M. Women, drinking and pregnancy. London: Tavistock Publications, 1987. 17
Downloaded from http://ije.oxfordjournals.org/ by guest on August 17, 2015
Forrest F, Florey C du V. The relation between maternal alcohol consumption and child development. The epidemiological evidence. J Public Health Med 1991; 13: 247-55. 2 Streissguth A P, Martin D C, Martin J C, Barr H M. The Seattle longitudinal prospective study on alcohol and pregnancy. Neurobehav Toxicol Teratol1981; 3: 223-33. 3 Landesman-Dwyer S, Keller L S, Streissguth A P. Naturalistic observations of newborns: Effects of maternal alcohol intake. Alcohol Clin Exp Res 1978; 2: 171-77. 4 Streissguth A P, Barr H M, Martin DC. Maternal alcohol use and neonatal habituation assessed with the Brazelton Scale. Child Dey 1983; 54: 1109-18. 5 Martin J, Martin D C, Lund C A, Streissguth A P. Maternal alcohol ingestion and cigarette smoking and their effects on newborn conditioning. Alcohol Clin Exp Res 1977; 1: 243-47. 6 Martin D C, Martin J C, Streissguth A P, Lund C A. Sucking frequency and amplitude in newborns as a function of maternal drinking and smoking. In: Currents in Alcoholism Vol V. Galanter M (ed.) New York: Grune and Stratton, 1979; pp. 359-66. 7 Streissguth A P, Barr H M, Martin D C, Herman C S. Effects of maternal alcohol, nicotine, and caffeine use during pregnancy on infant and motor development at eight months. Alcohol Clin Exp Res 1980; 4: 152-64. 8 Barr H M, Streissguth A P, Martin DC, Herman C S. Infant size at 8 months of age: Relationship to maternal use of alcohol, nicotine, and caffeine during pregnancy. Pediatrics 1984; 74: 336-41. 9 Streissguth A P, Martin D C, Barr H M, Sandman B MacG. Intrauterine alcohol and nicotine exposure: Attention and reaction time in 4-year-old children. Dey PsychoI1984; 20: 533-41. 10 Streissguth A P, Barr H M, Sampson P D, Darby B L, Martin D C. IQ at age 4 in relation to maternal alcohol use and smoking during pregnancy. Dey Psychol1989; 25: 3-11. 11 Streissguth A P, Barr H M, Sampson P D, Parrish-Johnson J C, Kirchner G L, Martin D C. Attention, distraction and reaction time at age 7 years and prenatal alcohol exposure. Neurobehav Toxicol Teratol 1986; 8: 717-25. 12 Streissguth A P, Barr H M, Sampson P D, Bookstein F L, Darby B L. Neurobehavioral effects of prenatal alcohol: Part 1. Research strategy. Neurotoxicol Teratol1989; 11: 461-76. 13 Sampson P D, Streissguth A P, Barr H M, Bookstein F L. Neurobehavioral effects of prenatal alcohol: Part II. Partial least squares analysis. Neurotoxicol Teratol1989; 11: 477-91. 14 Streissguth A P, Sampson P D, Bookstein F L, Barr H M. Neurobehavioral effects of prenatal alcohol: Part III. PLS analyses of neuropsychologic tests. Neurotoxicol Teratol1989; 11: 493-507. 15 Streissguth A P, Barr H M, Sampson P D. Moderate prenatal alcohol exposure: effects on child IQ and learning problems at age 7Y2 years. Alcohol Clin Exp Res 1990; 14: 662-69. 16 Streissguth A P, Martin D C, Buffington V E. Test-retest reliability of three scales derived from a quantity-frequency-variability assessment of self-reported alcohol consumption. Ann NY Acad Sci 1976; 273: 458-66. I
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