Growth restriction as a determinant of outcome in preterm discordant twins

OBJECTIVE: To estimate the influence of intrauterine growth restriction (IUGR) on the outcome of preterm discordant twins. METHODS: Medical records of preterm twins born at 24-34 weeks of gestation between 1995 and 2000 were reviewed. Significant discordancy was defined as more than 15% difference in birth weight. Small for gestational age (SGA) was defined as birth weight less than 10th percentile, according to a twin-adjusted gestational age nomogram. The smaller twins of 96 discordant twin pairs were evaluated. The SGA-discordant group included the smaller twin of a discordant pair who was also SGA (n = 46); the appropriate-for-gestational-age (AGA)-discordant group included the smaller twin of a discordant pair who was appropriate for gestational age (n = 50). RESULTS: Maternal age, incidence of maternal hypertension, antenatal steroids, and gestational age at delivery were similar between groups. Delivery for suspected fetal compromise complicated significantly more pregnancies in the SGA-discordant group than in the AGA-discordant group (45.6% versus 16%, P = .005), as did respiratory distress syndrome (RDS) (37% versus 8%, P < .05) and intraventricular hemorrhage (21.7% versus 6%, P = .024). Mortality or severe neonatal morbidity (defined as severe RDS, intraventricular hemorrhage grades 3-4, or necrotizing enterocolitis) were significantly higher among neonates in the SGA-discordant group than in the AGA-discordant group (19.5% versus 6%, P = .04). The risk for major morbidity was 7.7-fold greater in the SGA-discordant than in the AGA-discordant group, adjusted for gestational age. CONCLUSION: Growth restriction in preterm discordant twins is associated with a 7.7-fold increased risk for major neonatal morbidity. Therefore, discordant twins with IUGR require closer monitoring than discordant twins without IUGR.