330: Comparison of induced versus spontaneous onset of labor in term nulliparous twin pregnancies

Abstract

330 Comparison of induced versus spontaneous onset of abor in term nulliparous twin pregnancies Mark Hehir, Stephen Carroll, Rhona Mahony National Maternity Hospital, Holles St., Dept of Obstetrics and Gynaecology, ublin 2, Ireland OBJECTIVE: We sought to compare outcomes in nulliparous twin regnancies 36 weeks gestation undergoing induction of labor IOL) versus those in spontaneous. STUDY DESIGN: This was a prospective observational study carried out at a large maternity unit over an 11-year period from 2001-2011. Details of maternal demographics, intrapartum characteristics and neonatal outcomes of were recorded. Outcomes for all nulliparous twin pregnancies undergoing IOL were compared with those in spontaneous labor. RESULTS: During the study period there were 42718 nulliparous deiveries and 736 twin pregnancies 24 weeks gestation, giving an inidence of 1.7/100 nulliparous pregnancies. Approximately 48%(352/ 36) of nulliparas had a Cesarean delivery as a primary procedure. Of he remainder 45.3%(174/384) underwent IOL, and 17.1%(66/384) abored spontaneously, after 36 weeks gestation. Mothers who were nduced were older (31.5 5.2 years vs. 29.5 4.6 years; p 0.006), but had similar sized babies (p 0.39) to those in spontaneous labor. There was no difference in rates of oxytocin (p 0.19), epidural anesthesia (p 1.0) or duration of labor (p 0.4) between women who were induced or those in spontaneous labor. Women who underwent IOL were more likely to require Cesarean delivery than those in spontaneous labor (50.5% vs. 24.2%; p 0.002). They were also more likely to require instrumental delivery of at least one of their twins (39.1% vs. 26.5%; p 0.01). There was no difference in the rate of post-partum hemorrhage between the groups (p 0.44). Infants were not more likely to have an Apgar of 7 at 5min (p 0.68), a cord pH of 7.1 (p 0.73) or require admission to the neonatal unit (p 0.32) regardless of onset of labor. CONCLUSION: This study presents valuable data relating to IOL in nulliparous twin pregnancies after 36 weeks gestation. Women who were induced were more likely to be older, and require Cesarean or instrumental delivery. There was no evidence of increased maternal or neonatal morbidity associated with IOL. Model 1: ROC curve constructed using the strongest associations with shoulder dystocia (obesity, estimated fetal weight, GCT 140, and high station at complete).