Congenital anomalies are an independent risk factor for neonatal morbidityand perinatal mortality in preterm birth

Objective: To determine whether congenital anomalies are associated with a high rate of neonatal morbidity in preterm birth. Study design: 312 singlet ons (22-36 wk) with congenital anomalies that were delivered preterm were c ompared with a random sample of 936 preterm singleton without congenital an omalies. Data was obtained using the computerized birth discharge records. Statistical analysis included univariate and multivariate logistic regressi on analyses. Results: Three thousand five hundred and seventy-eight (3578) women with preterm births met the inclusion criteria (singleton with prenat al care). The prevalence of congenital anomalies in the study population wa s 8.7% (312/3578). Gestational age at delivery was significantly lower in t he congenital anomaly group compared with the control (32.0+/-3.7 SD vs. 34 .4+/-2.7 SD; p<0.001). The following pregnancy complications were higher in the group with congenital anomalies than in those without anomalies: sever e pregnancy induced hypertension (PIH), hydramnions, oligohydramnion, intra uterine growth restriction (IUGR), fetal distress, cesarean section, malpre sentation and mal position, abruption placenta, meconium stained amniotic f luid, 1 min Apgar score (<2), 5 min Apgar score (<7). Perinatal mortality r ates in 28-32 wk and 33-36 wk were significantly higher in the group with c ongenital anomalies than in the control group. Neonatal morbidity data (nec rotizing enterocolitis, respiratory distress syndrome, bronchopulmonary dys plasia, intraventricular hemorrhage, and sepsis) was available for 909 neon ates (239 with congenital anomalies and 670 without congenital anomalies). After adjusting for gestational age, the presence of congenital anomalies r emained strongly associated with neonatal morbidity (having one or more of the above mentioned conditions) (adjusted OR: 5.3, 95% CI 3.4-9.2). When ad justing for other confounding variables, congenital anomalies were strongly associated with neonatal morbidity (OR: 6.44, 95% CI 3.94-10.51), and peri natal mortality (OR: 3.08, 95% CI 2.04-4.65). In terms of attributable frac tion in our population of preterm births, the proportion of neonatal morbid ity and the proportion of perinatal mortality attributable to congenital ma lformation is 32% and 15%, respectively. Conclusion: Congenital anomalies i n preterm birth are associated with a higher rate of pregnancy complication s and are an independent risk factor for neonatal morbidity and perinatal m ortality. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.