Acta Obstet Gynecol Scand 58: 15-17, 1979
MATERNAL ALCOHOL AND TOBACCO CONSUMPTION AND THEIR ASSOCIATION WITH NAUSEA AND VOMITING DURING PREGNANCY Ruth E. Little and Ernest B. Hook From the Depurtment of Psychiatry urid Behuvioral Sciences und Depurtment of Epidemiology, UniverJity of W u ~ h i n g t o nGI-80, Secittle. WciJhington 98195, rind the Neil, Yorh Sttite Department of Hetilth rind Birth Defects Institute, Albony Medictil College, Albany, N e w Yorh 12208, U S A
Abstract. Nausea and vomiting during pregnancy (NVP) has been associated with favorable pregnancy outcome, though little is known about factors influencing its occurrence. In this study, information on NVP in 210 patients at a west coast health maintenance organization was obtained. Smoking and alcohol consumption before and during pregnancy were also estimated in two personal interviews during gestation. In all, 72% of the subjects had NVP in the first 4 months of pregnancy. Smokers had significantly less NVP than non-smokers (52% vs. 79%). Furthermore, NVP in smokers was negatively associated with alcohol consumption before and during pregnancy, with the stronger relation being for alcohol reported in the 6 months before pregnancy; only 46% of smokers drinking more than 4 fl. oz. of absolute alcohol daily in this period reported NVP, while 68% of smokers drinking less had NVP. For non-smokers, there was no relation between alcohol use in any period and NVP. The risk of NVP associated with pre-pregnancy drinking was not related to any change in alcohol consumption after conception. These results suggest an interaction between NVP, smoking, and reported alcohol consumption. The association of favorable pregnancy outcome with NVP may be in part a reflection of moderation in maternal alcohol and tobacco use.
The causes of nausea and vomiting during pregnancy (NVP) are unknown, although it occurs in about 75% of gravid women (2, 9, 11). There are, however, numerous reports that NVP is a favorable prognostic sign. In mothers of singleton infants, the risk of abortion prior to the 20th week of pregnancy is decreased if NVP is present (2, 5 , 9, 12). Liveborn children are reported to be of greater gestational age and higher birthweight than children born to women without NVP (2). The purpose of this paper is to report a serendipitous finding on the occurrence of NVP. The phenomenon appears to be related in a complex way to alcohol and tobacco consumption not
only during pregnancy, but possibly in the preconception period. Alcohol and tobacco use are, in turn, related to infant birthweight and perinatal mortality ( I , 4, 7, 10). Therefore the association of favorable pregnancy outcome with NVP may be confounded with maternal smoking and drinking habits. SUBJECTS AND METHODS The purpose of the study from which these data are drawn was to determine the relationship of regular maternal alcohol use to infant birth weight. Alcohol use was expressed in terms of average ounces of ethanol consumed daily. This value was termed “AA score”. Regular drinking was defined to be an AA score of 0.5 or more, which is equivalent to an average of at least one one-ounce shot of 100-proof whiskey daily. Subjects in the research were obstetrical patients in the prenatal clinic of a large health maintenance organization on the west coast. Nine hundred consecutive women who were paying members of the organization and who obtained prenatal care by the fourth month of gestation were contacted; 90% (806) agreed to participate in the investigation. The first 162 women eligible for study had an extensive personal interview in the fourth month of pregnancy, covering smoking habits, beverage consumption, and drug and medication use. AA scores for the 6 months before pregnancy and in the first 4 months of gestation were obtained. The remaining 644 women participating were screened for alcohol use. Sixty regular drinkers before or during early pregnancy were identified. and they were also interviewed in depth. Of the 222 interviewed women, 210 were still pregnant and available for follow-up in the eighth month of gestation. At this time, additional information on the variables noted above was obtained, and the degree of nausea throughout the pregnancy determined. The results described below are based on the data from these 210 women. For this report, AA scores have been classified into three groups: “regular” drinking, for AA scores of 0.5 or more; “infrequent” drinking, for AA scores of 0. I or less; Act[i
Oh.\tct G‘vnrc.o/ J c ( l f r d 5X I IY79)
16
R . E. Little and E . B . Hook
Table I . Alcohol consumption and smoking status before pregnancy and in early pregnancy (N=210) Percent of women in alcohol category ~~
Alcohol consumption
Non-smoker
Smoker
Before pregnancy Infrequent Occasional Regular Total number in group
38 % 24 38 153
I6 % 23 61 57
Early pregnancy Infrequent Occasional Regular Total number in group
54 % 34 12 160
30 % 36 34 50
and “occasional” drinking for AA scores between 0.1 and 0.5. A “smoker” lit an average of at least one cigarette per day. Occurrence of NVP refers to nausea and vomiting in the first 4 months of pregnancy, as reported by the subject. For simplicity, the 6 months prior to conception is referred to as “before pregnancy”, while the first 4 months of gestation is “early pregnancy”.
RESULTS Of the 2 10 subjects in this sample, 72 % experienced NVP. Smoking and drinking habits of the sample before pregnancy and in early pregnancy are shown in Table I . Fifty-seven women (27 %) were smokers before pregnancy, and seven of them stopped in early pregnancy. There was a significant decrease in drinking after conception; this phenomenon has been explored elsewhere (3, 6). Alcohol and tobacco use were strongly correlated in both periods. Table I1 shows NVP by alcohol and tobacco use both before pregnancy and in early pregnancy. In general, smokers experienced significantly less NVP than non-smokers. For smokers, regular drinking before pregnancy was significantly related to occurrence of NVP, with less than half of the women who smoked and drank regularly in this period reporting NVP. The same relationship was evident for early pregnancy drinking and smoking, but it was less marked and not significant. For nonsmokers, alcohol use was unrelated to occurrence of NVP. An interesting question is to what extent the low rate of NVP among regular drinking smokers contributed to their habits. One would of course expect
nausea and vomiting to discourage regular alcohol and tobacco use. Change in smoking in response to NVP is difficult to assess because of the small number in the sample. However, 88% of the smokers continued to smoke in early pregnancy although more than half of them were nauseated. Change in alcohol use in response to NVP is more readily determined. Seventy-two percent of subjects who decreased alcohol consumption in early pregnancy had NVP, while 73% of those maintaining or increasing alcohol consumption after conception had NVP. Change in alcohol consumption in early pregnancy was unrelated to NVP for smokers and non-smokers alike. The absence of any relationship also held in all three drinking groups. In particular, 64% of the subjects who maintained regular drinking both before and in early pregnancy had NVP, compared with 70% of regular drinkers who dropped to a lower category in early pregnancy. The difference is not significant. DISCUSSION AND SUMMARY The data presented above indicate that nausea and vomiting during pregnancy occurred less frequently in women who were both regular drinkers and smokers. This result is consistent with the findings of Mau & Netter, who report that heavier drinkers
Table 11. Occurrence of NVP in smokers and nonsmokers by alcohol consumption (N=210) Percent with NVP Alcohol consumption Before pregnancy Infrequent Occasional Regu 1ar All subjects Early pregnancy Infrequent Occasional Regular
All subjects
Non-smoker
Smoker
78 % 78 81 78 %a
78 %b 62b 46b
80 % 76 79 79 %“
60 % 50 47 52 %”
54 %”
The difference in percentage of smokers with NVP versus percentage of non-smokers with NVP is significant at the 0.01 level by the x* test. For smokers, the association between AA score before pregnancy and occurrence of NVP is significant at the 0.05 level by the Mann-Whitney U-test (two-tail, corrected for ties).
a
Alcohol, tobacco, and nauseu dirring pregnancy during pregnancy used fewer anti-emetic drugs (8). It also corroborates the work of Kullander & Kallen, who found a relatively low rate of NVP among smokers (5). In this sample, however, use of both alcohol and tobacco was necessary for the relationship with decreased rate of NVP to be evident. The relationship is more complex than it first appears. Our original hypothesis was that NVP would be less frequent in women who drank or smoked regularly in early pregnancy. We are somewhat at a loss to explain the fact that the hypothesis holds more strongly for pre-pregnancy habits than for habits after conception, and that NVP does not appear to be a significant factor in the change in alcohol use during the early months of pregnancy. In any case, an alcohol-tobacco-NVP interaction has implications for fetal welfare. Nausea and vomiting in early pregnancy may be a favorable prognostic sign because women who experience it are less likely to be regular drinkers and smokers. Whether NVP has an influence apart from these remains to be seen. ACKNOWLEDGEMENTS This work was partially supported by grant number AA02174-01 from the National Institute on Alcohol Abuse and Alcoholism and by the Spencer Foundation.
17
related to outcome of pregnancy. Obstet 4 2 7 4 3 1, 1967. 3. Hook, E. B.: Changes in tobacco smoking and ingestion of alcohol and caffeinated beverages during early pregnancy: Are these consequences, in part, of fetoprotective mechanisms diminishing maternal exposure to embryotoxins? In Birth Defects: Risks and Consequences (ed. S. Kelly et a].). Academic Press. New York, 1976. 4. Kaminski, M., Rumeau-Roquette, C. & Schwartz. D.: Consommation d'alcool chez les femmes enceintes et issue de la grossesse. Rev. Epidem, et Sante Pub1 24: 27-40, 1976. 5. Kullander, S. & Kallen, B.: A prospective study of drugs and pregnancy. 11. Anti-emetic drugs. Acta Obstet Gynecol Scand 55: 105-1 I I , 1976. 6. Little, R., Schultz, F. & Mandell, W.: Drinkingduring pregnancy. J Stud Alc37: 375-379, 1976. 7. Little, R. E.: Moderate alcohol use during pregnancy and decreased infant birth weight. Amer J Pub Hith 67: 11541156. 1977. 8. Mau, G. & Netter, P.: Kaffee- und Alkoholkonsum. Risikofaktoren in der Schwangerschaft? Geburtsh Frauenheilk 34: I0 18-1022, 1974. 9. Medalie, J. H.: Relationship between nausea and/or vomiting in early pregnancy and abortion. Lancet ii: 117-1 19, 1957. 10. Meyer, M . B., Tonascia, J. A. & Buck, C.: The interrelationship of maternal smoking and increased perinatal mortality with other risk factors. Amer J Epid 100: 443452, 1975. 1 1 . Midwinter, A.: Vomiting in pregnancy. The Practitioner206: 743-750, 1971. 12. Yerushalmy, J. & Milkovich, L.: Evaluation of the teratogenic effect of meclizine in man. Am J Obstet Gynecol93: 553-562, 1965. Submitted for publication Sept. 7 , I977
REFERENCES 1. Andrews, J . & McGarry, J. M.: A community study of smoking in pregnancy. J Obstet Gynaecol Br Commonw 79: 1057-1073, 1972. 2. Brandes, J. M.: First trimester nausea and vomiting as
2-792866
Ruth E. Little Sc.D. Dept. of Psychiatry and Behavioral Sciences University of Washington Seattle, Wa 98195 USA
Acru Obsrrr Gynecol Sctrnd 58 I19791
MATERNAL ALCOHOL AND TOBACCO CONSUMPTION AND THEIR ASSOCIATION WITH NAUSEA AND VOMITING DURING PREGNANCY Ruth E. Little and Ernest B. Hook From the Depurtment of Psychiatry urid Behuvioral Sciences und Depurtment of Epidemiology, UniverJity of W u ~ h i n g t o nGI-80, Secittle. WciJhington 98195, rind the Neil, Yorh Sttite Department of Hetilth rind Birth Defects Institute, Albony Medictil College, Albany, N e w Yorh 12208, U S A
Abstract. Nausea and vomiting during pregnancy (NVP) has been associated with favorable pregnancy outcome, though little is known about factors influencing its occurrence. In this study, information on NVP in 210 patients at a west coast health maintenance organization was obtained. Smoking and alcohol consumption before and during pregnancy were also estimated in two personal interviews during gestation. In all, 72% of the subjects had NVP in the first 4 months of pregnancy. Smokers had significantly less NVP than non-smokers (52% vs. 79%). Furthermore, NVP in smokers was negatively associated with alcohol consumption before and during pregnancy, with the stronger relation being for alcohol reported in the 6 months before pregnancy; only 46% of smokers drinking more than 4 fl. oz. of absolute alcohol daily in this period reported NVP, while 68% of smokers drinking less had NVP. For non-smokers, there was no relation between alcohol use in any period and NVP. The risk of NVP associated with pre-pregnancy drinking was not related to any change in alcohol consumption after conception. These results suggest an interaction between NVP, smoking, and reported alcohol consumption. The association of favorable pregnancy outcome with NVP may be in part a reflection of moderation in maternal alcohol and tobacco use.
The causes of nausea and vomiting during pregnancy (NVP) are unknown, although it occurs in about 75% of gravid women (2, 9, 11). There are, however, numerous reports that NVP is a favorable prognostic sign. In mothers of singleton infants, the risk of abortion prior to the 20th week of pregnancy is decreased if NVP is present (2, 5 , 9, 12). Liveborn children are reported to be of greater gestational age and higher birthweight than children born to women without NVP (2). The purpose of this paper is to report a serendipitous finding on the occurrence of NVP. The phenomenon appears to be related in a complex way to alcohol and tobacco consumption not
only during pregnancy, but possibly in the preconception period. Alcohol and tobacco use are, in turn, related to infant birthweight and perinatal mortality ( I , 4, 7, 10). Therefore the association of favorable pregnancy outcome with NVP may be confounded with maternal smoking and drinking habits. SUBJECTS AND METHODS The purpose of the study from which these data are drawn was to determine the relationship of regular maternal alcohol use to infant birth weight. Alcohol use was expressed in terms of average ounces of ethanol consumed daily. This value was termed “AA score”. Regular drinking was defined to be an AA score of 0.5 or more, which is equivalent to an average of at least one one-ounce shot of 100-proof whiskey daily. Subjects in the research were obstetrical patients in the prenatal clinic of a large health maintenance organization on the west coast. Nine hundred consecutive women who were paying members of the organization and who obtained prenatal care by the fourth month of gestation were contacted; 90% (806) agreed to participate in the investigation. The first 162 women eligible for study had an extensive personal interview in the fourth month of pregnancy, covering smoking habits, beverage consumption, and drug and medication use. AA scores for the 6 months before pregnancy and in the first 4 months of gestation were obtained. The remaining 644 women participating were screened for alcohol use. Sixty regular drinkers before or during early pregnancy were identified. and they were also interviewed in depth. Of the 222 interviewed women, 210 were still pregnant and available for follow-up in the eighth month of gestation. At this time, additional information on the variables noted above was obtained, and the degree of nausea throughout the pregnancy determined. The results described below are based on the data from these 210 women. For this report, AA scores have been classified into three groups: “regular” drinking, for AA scores of 0.5 or more; “infrequent” drinking, for AA scores of 0. I or less; Act[i
Oh.\tct G‘vnrc.o/ J c ( l f r d 5X I IY79)
16
R . E. Little and E . B . Hook
Table I . Alcohol consumption and smoking status before pregnancy and in early pregnancy (N=210) Percent of women in alcohol category ~~
Alcohol consumption
Non-smoker
Smoker
Before pregnancy Infrequent Occasional Regular Total number in group
38 % 24 38 153
I6 % 23 61 57
Early pregnancy Infrequent Occasional Regular Total number in group
54 % 34 12 160
30 % 36 34 50
and “occasional” drinking for AA scores between 0.1 and 0.5. A “smoker” lit an average of at least one cigarette per day. Occurrence of NVP refers to nausea and vomiting in the first 4 months of pregnancy, as reported by the subject. For simplicity, the 6 months prior to conception is referred to as “before pregnancy”, while the first 4 months of gestation is “early pregnancy”.
RESULTS Of the 2 10 subjects in this sample, 72 % experienced NVP. Smoking and drinking habits of the sample before pregnancy and in early pregnancy are shown in Table I . Fifty-seven women (27 %) were smokers before pregnancy, and seven of them stopped in early pregnancy. There was a significant decrease in drinking after conception; this phenomenon has been explored elsewhere (3, 6). Alcohol and tobacco use were strongly correlated in both periods. Table I1 shows NVP by alcohol and tobacco use both before pregnancy and in early pregnancy. In general, smokers experienced significantly less NVP than non-smokers. For smokers, regular drinking before pregnancy was significantly related to occurrence of NVP, with less than half of the women who smoked and drank regularly in this period reporting NVP. The same relationship was evident for early pregnancy drinking and smoking, but it was less marked and not significant. For nonsmokers, alcohol use was unrelated to occurrence of NVP. An interesting question is to what extent the low rate of NVP among regular drinking smokers contributed to their habits. One would of course expect
nausea and vomiting to discourage regular alcohol and tobacco use. Change in smoking in response to NVP is difficult to assess because of the small number in the sample. However, 88% of the smokers continued to smoke in early pregnancy although more than half of them were nauseated. Change in alcohol use in response to NVP is more readily determined. Seventy-two percent of subjects who decreased alcohol consumption in early pregnancy had NVP, while 73% of those maintaining or increasing alcohol consumption after conception had NVP. Change in alcohol consumption in early pregnancy was unrelated to NVP for smokers and non-smokers alike. The absence of any relationship also held in all three drinking groups. In particular, 64% of the subjects who maintained regular drinking both before and in early pregnancy had NVP, compared with 70% of regular drinkers who dropped to a lower category in early pregnancy. The difference is not significant. DISCUSSION AND SUMMARY The data presented above indicate that nausea and vomiting during pregnancy occurred less frequently in women who were both regular drinkers and smokers. This result is consistent with the findings of Mau & Netter, who report that heavier drinkers
Table 11. Occurrence of NVP in smokers and nonsmokers by alcohol consumption (N=210) Percent with NVP Alcohol consumption Before pregnancy Infrequent Occasional Regu 1ar All subjects Early pregnancy Infrequent Occasional Regular
All subjects
Non-smoker
Smoker
78 % 78 81 78 %a
78 %b 62b 46b
80 % 76 79 79 %“
60 % 50 47 52 %”
54 %”
The difference in percentage of smokers with NVP versus percentage of non-smokers with NVP is significant at the 0.01 level by the x* test. For smokers, the association between AA score before pregnancy and occurrence of NVP is significant at the 0.05 level by the Mann-Whitney U-test (two-tail, corrected for ties).
a
Alcohol, tobacco, and nauseu dirring pregnancy during pregnancy used fewer anti-emetic drugs (8). It also corroborates the work of Kullander & Kallen, who found a relatively low rate of NVP among smokers (5). In this sample, however, use of both alcohol and tobacco was necessary for the relationship with decreased rate of NVP to be evident. The relationship is more complex than it first appears. Our original hypothesis was that NVP would be less frequent in women who drank or smoked regularly in early pregnancy. We are somewhat at a loss to explain the fact that the hypothesis holds more strongly for pre-pregnancy habits than for habits after conception, and that NVP does not appear to be a significant factor in the change in alcohol use during the early months of pregnancy. In any case, an alcohol-tobacco-NVP interaction has implications for fetal welfare. Nausea and vomiting in early pregnancy may be a favorable prognostic sign because women who experience it are less likely to be regular drinkers and smokers. Whether NVP has an influence apart from these remains to be seen. ACKNOWLEDGEMENTS This work was partially supported by grant number AA02174-01 from the National Institute on Alcohol Abuse and Alcoholism and by the Spencer Foundation.
17
related to outcome of pregnancy. Obstet 4 2 7 4 3 1, 1967. 3. Hook, E. B.: Changes in tobacco smoking and ingestion of alcohol and caffeinated beverages during early pregnancy: Are these consequences, in part, of fetoprotective mechanisms diminishing maternal exposure to embryotoxins? In Birth Defects: Risks and Consequences (ed. S. Kelly et a].). Academic Press. New York, 1976. 4. Kaminski, M., Rumeau-Roquette, C. & Schwartz. D.: Consommation d'alcool chez les femmes enceintes et issue de la grossesse. Rev. Epidem, et Sante Pub1 24: 27-40, 1976. 5. Kullander, S. & Kallen, B.: A prospective study of drugs and pregnancy. 11. Anti-emetic drugs. Acta Obstet Gynecol Scand 55: 105-1 I I , 1976. 6. Little, R., Schultz, F. & Mandell, W.: Drinkingduring pregnancy. J Stud Alc37: 375-379, 1976. 7. Little, R. E.: Moderate alcohol use during pregnancy and decreased infant birth weight. Amer J Pub Hith 67: 11541156. 1977. 8. Mau, G. & Netter, P.: Kaffee- und Alkoholkonsum. Risikofaktoren in der Schwangerschaft? Geburtsh Frauenheilk 34: I0 18-1022, 1974. 9. Medalie, J. H.: Relationship between nausea and/or vomiting in early pregnancy and abortion. Lancet ii: 117-1 19, 1957. 10. Meyer, M . B., Tonascia, J. A. & Buck, C.: The interrelationship of maternal smoking and increased perinatal mortality with other risk factors. Amer J Epid 100: 443452, 1975. 1 1 . Midwinter, A.: Vomiting in pregnancy. The Practitioner206: 743-750, 1971. 12. Yerushalmy, J. & Milkovich, L.: Evaluation of the teratogenic effect of meclizine in man. Am J Obstet Gynecol93: 553-562, 1965. Submitted for publication Sept. 7 , I977
REFERENCES 1. Andrews, J . & McGarry, J. M.: A community study of smoking in pregnancy. J Obstet Gynaecol Br Commonw 79: 1057-1073, 1972. 2. Brandes, J. M.: First trimester nausea and vomiting as
2-792866
Ruth E. Little Sc.D. Dept. of Psychiatry and Behavioral Sciences University of Washington Seattle, Wa 98195 USA
Acru Obsrrr Gynecol Sctrnd 58 I19791
