Comparison study between induced and spontaneous term and preterm births of small-for-gestational-age neonates

Objective: To compare perinatal and maternal outcome between induced and spontaneous small-for-gestational-age (SGA) neonates at term and preterm deliveries. Study design: A cross-sectional study was designed and two groups were identified at each gestational age: study group - SGA neonates born after induction of labor, comparison group - SGA neonates born after spontaneous onset of labor. SGA was decoded as birth weight below 10th percentile. The population consisted of 367 consecutive SGA singleton preterm neonates (24-36 weeks' gestation) and 3921 term SGA neonates (37-42 weeks' gestation) delivered between 1990 and 1997. Patients with antepartum death and congenital anomalies were excluded from this study. Results: The prevalence of SGA neonates among preterm deliveries was significantly higher than among term deliveries (9.3 versus 6.1%, P<0.001). The rate of induction of labor among preterm SGA deliveries was significantly higher than term SGA deliveries (17.7 versus 13.4%, P=0.002). The rates hypertensive disorders, suspected IUGR, placental abruption, cesarean section, chorioamnionitis and endometritis were significantly higher among preterm SGA than in term SGA. A multiple logistic regression analysis demonstrated that suspected IUGR, severe PIH (but not mild PIH), chronic hypertension and placental abruption were independent risk factors for induction of labor among preterm SGA neonates. In addition to these factors, oligohydramnios was considered to be an independent risk factor only among term SGA. No significant differences were found in the mean birthweight and post-partum death rates between the induced and spontaneous preterm and term SGA. The incidence of Apgar score<7 at 5min was significantly lower only among induced term SGA. Conclusions: Induction of labor in preterm SGA neonates is performed mainly due to maternal severe hypertension disorders. The indications for induction of labor among term SGA include maternal hypertensive disorders (mild or severe) as well as neonatal status, represented mainly by oligohydramnios. In addition, induction of labor in preterm or term SGA neonates does not change neonatal outcome. Moreover, since no evidence of improved neonatal outcome was demonstrated in either indicated group, preterm or term, the question of timing and indications for induction of labor should be discussed.