AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 7, NUMBER 2 April 1990
IMPROVED SURVIVAL AND NEURODEVELOPMENTAL OUTCOME FOR INFANTS LESS THAN 801 GRAMS BIRTHWEIGHT Howard W. Kilbride, M.D., Donna K. Daily, M.D., Katherine Claflin, M.D.* Robert T. Hall, M.D., Dev Maulik, M.D., Ph.D., and Howard O. Grundy, M.D.f
We reviewed the perinatal management and subsequent outcome of infants 401 to 800 gmbirthweight delivered in 1983 to 1985 compared with those born in 1980 to 1982. Intrapartum fetal heart rate monitoring, cesarean section delivery, attempted delivery room resuscitation, and 5-minuteApgar scores greater than 5 were more frequent in 1983 to 1985. Significantly greater neonatal survival was evident for infants 500 to 700 gm birthweight (31 %) and 24 to 27 weeks' gestation (45%) in 1983 to 1985, p < 0.005. Infant birthweight, gestational age, gender, and 5-minute Apgar score, in addition to intrapartum tocolysis use, were predictors of higher survival by stepwise discriminant analysis. At a mean follow-up of 27 months, 13% (6 of 46) born in 1983 to 1985 had major disability compared with 67% (6 of 9) of infants born in 1980 to 1982. There has been a significant increase in survival and improvement in neurodevelopmental follow-up status for infants less than 801 gm birthweight. These improved outcome data should be considered by caregivers providing perinatal management and counseling parents regarding extremely low birthweight infants.
Increased survival of extremely low birthweight (BW) infants has only recently been documented.1-2 Since the physician's knowledge and attitude regarding neonatal survival and outcome may greatly affect perinatal management decisions, it is to be expected that there is great variability in care provided for extremely low BW infants.3"6 To evaluate recent alterations in perinatal management and associated changes in neonatal survival and long-term outcome of infants less than 801 gm BW, we reviewed data of recently born infants (1983 to 1985) compared with those born during the preceding 3 years (1980 to 1982).
PATIENTS AND METHODS
Inborn infants 401 to 800 gm BW delivered between January 1, 1980, and December 31, 1985, were included in the study. Maternal records were reviewed to determine the incidence of obstetric complications and associated perinatal management (Tables 1 and 2). Maternal-fetal obstetric consultation became available in 1983. Since that time, tocolysis with betasympathomimetics or magnesium sulfate was generally provided to the population studied unless contraindicated. Intramuscular betamethasone for
Department of Pediatrics, Children's Mercy Hospital; Department of Obstetrics-Gynecology, Truman Medical Center; and Department of Perinatology, St. Luke's Hospital, University of Missouri School of Medicine, Kansas City, Missouri Reprint requests: Dr. Kilbride, Children's Mercy Hospital, 24th at Gillham, Kansas City, MO 64108 * Present address: Department of Pediatrics, University of Kansas Medical Center, Kansas City, Kansas 66103 +
Present address: Director, Maternal-Fetal Medicine and Medical Genetics, Christ Hospital and Medical Center, Oak Lawn, IL 60453
160
Copyright © 1990 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: University of British Columbia. Copyrighted material.
ABSTRACT
SURVIVAL AND NEURODEVELOPMENT OF LOW BIRTHWEIGHT INFANTS/Kilbride et al.
1980-1982 Antenatal steroids Intrapartum fetal heart rate monitor Intrapartum toco lysis Cesarean section delivery (singleton gestation)
1983-1985
p Value
No.
%
No.
%
4 32
7 55
17 110
13 81
NS 1 year of age surviving with specific neurodevelopmental disabilities and combined major disability, 1980 to 1982 and 1983 to 1985.
daily all infants at greater weights. In association with increased delivery room care for infants in the later years, significantly improved Apgar scores and a lower incidence of neonatal acidosis were documented. Our analysis demonstrated for 1983 to 1985 the greatest predictors of survival were infant variables. Female gender, heavier BW, and greater gestational maturity were each independently related to survival. These data were not surprising and are consistent with findings of previous studies. BW and gestational age are both important determinants of neonatal survival.13 Additionally, males have consistently been found at a disadvantage regarding many neonatal disease states and overall survival.14 The only obstetric management factor with independent predictive value of survival was intrapartum tocolytic use. Sympathomimetic agents may potentially accelerate surfactant production and thereby decrease mortality from respiratory distress syndrome.15 However, women who receive tocolysis are likely to be clinically stable and unique from those who do not receive tocolysis (that is, less cervical dilation, absence of vaginal bleeding). These factors, rather than drug effect, may have accounted for greater neonatal survival.16 Discontinuation of benzyl alcohol in 1982 accounted for some improved survival in later years.17 This preservative is a neurotoxic agent, presenting the greatest hazard to lowest weight infants.I2 In our study at least 5 of the infants who died in 1980 to 1982 had symptoms compatible with benzyl alcohol toxicity. This agent may have been an unrecognized factor in additional mortality and morbidity.18 There have been concerns that the reported improved neonatal survival for extremely low BW infants is largely artifactual, since many of these infants die beyond the 28-day neonatal period.19 However, our data suggest that even when given intensive support, extremely tiny babies who die do so generally within the first week of hospitalization. Postneonatal deaths (between 1 month and 1 year of age) occurred in only 8% of our neonatal survivors. The leading cause of death for infants was hypoxemia secondary to respiratory distress syndrome. Since our current management includes maximal ventilatory support for all infants in the intensive care unit, we anticipate no change in this experience until a new technology (such as surfactant replacement) is introduced. Our data reflect not only recent improvement in survival for extremely low BW infants, but also significantly better neurodevelopmental outcome for those who do survive. Six of nine surviving infants from 1980 to 1982 had major disability evident by chart review. More subtle, but significantly important abnormalities may have been overlooked by this review so that the percentage of disabled infants for the early time period should be considered a minimum estimate. After a comprehensive evaluation of the 1983 to 1985 survivors, a significantly lower incidence of major disability (13%) was recognized. This
Downloaded by: University of British Columbia. Copyrighted material.
AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 7, NUMBER 2 April 1990
lower incidence of disabilities is especially notable since surviving infants of 1983 to 1985 were on average less mature and had a lower BW than those of 1980 to 1982. The low incidences of disability and, specifically, of CP (4%) are comparable to those described for infants of 1000 to 1500 gm BW.20 These data support the concept that perinatal intensive care is associated with less morbidity as well as greater neonatal survival for extremely low BW infants. Although severe handicaps were uncommon, 41% of the infants had suspect evaluations, with a CMDI in the intermediate range (68 to 83). Verbal skills were delayed in most patients. In this regard the high incidence of conductive hearing loss (15%) may be important and needs further study. The additional impact of socioeconomic status has been recognized but was not investigated in this study.21 Major disabilities were disproportionately evident among infants less than 601 gm BW. Additional follow-up will be necessary to determine if greater survival in this select group will be associated with a decline in the rate of handicaps. Our data point out that over a recent 6-year period there have been significant changes in clinical perinatal practices for infants less than 801 gm BW. Simultaneously, there has been a significant increase in survival and improved neurodevelopmental outcome for these infants. Health care providers need to be aware of current data in order to provide appropriate management and counseling regarding extremely low BW infants.
REFERENCES 1.
Hack M, Fanaroff AA: Changes in the delivery room care of the extremely small infant (
IMPROVED SURVIVAL AND NEURODEVELOPMENTAL OUTCOME FOR INFANTS LESS THAN 801 GRAMS BIRTHWEIGHT Howard W. Kilbride, M.D., Donna K. Daily, M.D., Katherine Claflin, M.D.* Robert T. Hall, M.D., Dev Maulik, M.D., Ph.D., and Howard O. Grundy, M.D.f
We reviewed the perinatal management and subsequent outcome of infants 401 to 800 gmbirthweight delivered in 1983 to 1985 compared with those born in 1980 to 1982. Intrapartum fetal heart rate monitoring, cesarean section delivery, attempted delivery room resuscitation, and 5-minuteApgar scores greater than 5 were more frequent in 1983 to 1985. Significantly greater neonatal survival was evident for infants 500 to 700 gm birthweight (31 %) and 24 to 27 weeks' gestation (45%) in 1983 to 1985, p < 0.005. Infant birthweight, gestational age, gender, and 5-minute Apgar score, in addition to intrapartum tocolysis use, were predictors of higher survival by stepwise discriminant analysis. At a mean follow-up of 27 months, 13% (6 of 46) born in 1983 to 1985 had major disability compared with 67% (6 of 9) of infants born in 1980 to 1982. There has been a significant increase in survival and improvement in neurodevelopmental follow-up status for infants less than 801 gm birthweight. These improved outcome data should be considered by caregivers providing perinatal management and counseling parents regarding extremely low birthweight infants.
Increased survival of extremely low birthweight (BW) infants has only recently been documented.1-2 Since the physician's knowledge and attitude regarding neonatal survival and outcome may greatly affect perinatal management decisions, it is to be expected that there is great variability in care provided for extremely low BW infants.3"6 To evaluate recent alterations in perinatal management and associated changes in neonatal survival and long-term outcome of infants less than 801 gm BW, we reviewed data of recently born infants (1983 to 1985) compared with those born during the preceding 3 years (1980 to 1982).
PATIENTS AND METHODS
Inborn infants 401 to 800 gm BW delivered between January 1, 1980, and December 31, 1985, were included in the study. Maternal records were reviewed to determine the incidence of obstetric complications and associated perinatal management (Tables 1 and 2). Maternal-fetal obstetric consultation became available in 1983. Since that time, tocolysis with betasympathomimetics or magnesium sulfate was generally provided to the population studied unless contraindicated. Intramuscular betamethasone for
Department of Pediatrics, Children's Mercy Hospital; Department of Obstetrics-Gynecology, Truman Medical Center; and Department of Perinatology, St. Luke's Hospital, University of Missouri School of Medicine, Kansas City, Missouri Reprint requests: Dr. Kilbride, Children's Mercy Hospital, 24th at Gillham, Kansas City, MO 64108 * Present address: Department of Pediatrics, University of Kansas Medical Center, Kansas City, Kansas 66103 +
Present address: Director, Maternal-Fetal Medicine and Medical Genetics, Christ Hospital and Medical Center, Oak Lawn, IL 60453
160
Copyright © 1990 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: University of British Columbia. Copyrighted material.
ABSTRACT
SURVIVAL AND NEURODEVELOPMENT OF LOW BIRTHWEIGHT INFANTS/Kilbride et al.
1980-1982 Antenatal steroids Intrapartum fetal heart rate monitor Intrapartum toco lysis Cesarean section delivery (singleton gestation)
1983-1985
p Value
No.
%
No.
%
4 32
7 55
17 110
13 81
NS 1 year of age surviving with specific neurodevelopmental disabilities and combined major disability, 1980 to 1982 and 1983 to 1985.
daily all infants at greater weights. In association with increased delivery room care for infants in the later years, significantly improved Apgar scores and a lower incidence of neonatal acidosis were documented. Our analysis demonstrated for 1983 to 1985 the greatest predictors of survival were infant variables. Female gender, heavier BW, and greater gestational maturity were each independently related to survival. These data were not surprising and are consistent with findings of previous studies. BW and gestational age are both important determinants of neonatal survival.13 Additionally, males have consistently been found at a disadvantage regarding many neonatal disease states and overall survival.14 The only obstetric management factor with independent predictive value of survival was intrapartum tocolytic use. Sympathomimetic agents may potentially accelerate surfactant production and thereby decrease mortality from respiratory distress syndrome.15 However, women who receive tocolysis are likely to be clinically stable and unique from those who do not receive tocolysis (that is, less cervical dilation, absence of vaginal bleeding). These factors, rather than drug effect, may have accounted for greater neonatal survival.16 Discontinuation of benzyl alcohol in 1982 accounted for some improved survival in later years.17 This preservative is a neurotoxic agent, presenting the greatest hazard to lowest weight infants.I2 In our study at least 5 of the infants who died in 1980 to 1982 had symptoms compatible with benzyl alcohol toxicity. This agent may have been an unrecognized factor in additional mortality and morbidity.18 There have been concerns that the reported improved neonatal survival for extremely low BW infants is largely artifactual, since many of these infants die beyond the 28-day neonatal period.19 However, our data suggest that even when given intensive support, extremely tiny babies who die do so generally within the first week of hospitalization. Postneonatal deaths (between 1 month and 1 year of age) occurred in only 8% of our neonatal survivors. The leading cause of death for infants was hypoxemia secondary to respiratory distress syndrome. Since our current management includes maximal ventilatory support for all infants in the intensive care unit, we anticipate no change in this experience until a new technology (such as surfactant replacement) is introduced. Our data reflect not only recent improvement in survival for extremely low BW infants, but also significantly better neurodevelopmental outcome for those who do survive. Six of nine surviving infants from 1980 to 1982 had major disability evident by chart review. More subtle, but significantly important abnormalities may have been overlooked by this review so that the percentage of disabled infants for the early time period should be considered a minimum estimate. After a comprehensive evaluation of the 1983 to 1985 survivors, a significantly lower incidence of major disability (13%) was recognized. This
Downloaded by: University of British Columbia. Copyrighted material.
AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 7, NUMBER 2 April 1990
lower incidence of disabilities is especially notable since surviving infants of 1983 to 1985 were on average less mature and had a lower BW than those of 1980 to 1982. The low incidences of disability and, specifically, of CP (4%) are comparable to those described for infants of 1000 to 1500 gm BW.20 These data support the concept that perinatal intensive care is associated with less morbidity as well as greater neonatal survival for extremely low BW infants. Although severe handicaps were uncommon, 41% of the infants had suspect evaluations, with a CMDI in the intermediate range (68 to 83). Verbal skills were delayed in most patients. In this regard the high incidence of conductive hearing loss (15%) may be important and needs further study. The additional impact of socioeconomic status has been recognized but was not investigated in this study.21 Major disabilities were disproportionately evident among infants less than 601 gm BW. Additional follow-up will be necessary to determine if greater survival in this select group will be associated with a decline in the rate of handicaps. Our data point out that over a recent 6-year period there have been significant changes in clinical perinatal practices for infants less than 801 gm BW. Simultaneously, there has been a significant increase in survival and improved neurodevelopmental outcome for these infants. Health care providers need to be aware of current data in order to provide appropriate management and counseling regarding extremely low BW infants.
REFERENCES 1.
Hack M, Fanaroff AA: Changes in the delivery room care of the extremely small infant (
