Pregnancy outcomes associated with intrauterine growth restriction

OBJECTIVE: This study was undertaken to examine the incidence of intrauterine growth restriction (IUGR) and neonatal outcomes of pregnancies delivered from 26 to 41 weeks' gestation. STUDY DESIGN: A retrospective review of a linked database of all deliveries in California in 1994 through 1996 that were reported to the Office of Statewide Health and Planning Development. MATERIAL AND METHODS: A database of maternal and neonatal discharge summaries linked to birth and death certificates were examined for gestational age at delivery, diagnosis of IUGR, respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), length of stay, and hospital charges (CHA). More than 1.4 million singleton deliveries were examined by week of gestation and separated into the presence or absence of IUGR and then examined for adverse neonatal outcomes. RESULTS: The frequency of IUGR was increased in the preterm newborn infants compared with those at 40 weeks' gestation (26 = 8.9%, 27 = 7.7%, 28 = 9.8%, 29 = 10.5%, 30 = 12.3%, 31 = 9.1%, 32 = 7.5%, 33 = 6.6%, 34 = 5.6%, 35 = 5.0%, 36 = 4.4%, 37 = 3.7%, 38 = 2.3%, 39 = 1.5%, 40 = 1.1%). Up to 28 weeks' gestation, the incidence of RDS was higher for infants without IUGR compared with infants with IUGR (not significant). Starting at 29 weeks' gestation, RDS was higher for infants with IUGR. Initially not significant, this difference was statistically significant starting from 34 weeks. The findings were similar for IVH, NEC, and length of stay. The threshold at which the relationship between the presence of lUGR and the outcome flipped was 30, 28, and 29 weeks, whereas significance was observed at 34, 35, and 30 weeks, respectively. CHA were always higher for those patients with lUGR but became significantly higher after 29 weeks. CONCLUSION: IUGR was increased with prematurity and may represent an important risk factor to check for in women who present with preterm labor. Prematurity associated with adverse neonatal outcomes (RDS, IVH, NEC, CHA) were largely unaffected by IUGR until the third trimester. From then on, all adverse outcomes were increased compared with normally grown premature infants, suggesting a need for closer surveillance for lUGR in the third trimester.