174: Induction of labor in nulliparous women with IUGR and abnormal umbilical artery blood flow: data from a large multi-center prospective study

The aim of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) Study was to evaluate the optimal management of fetuses with EFW<10th centile. The objective of this secondary analysis was to describe the success rate of induction and overall labor outcomes in nulliparous patients with IUGR. Over 1,100 consecutive ultrasound-dated singleton pregnancies with EFW<10th centile were subjected to sonographic surveillance at least every two weeks with biometry and multi-vessel Doppler assessment. Labor and perinatal outcomes of nulliparous patients with EFW<10th centile and associated abnormal UA Doppler on last sonogram prior to delivery were studied. Of 595 nulliparous PORTO patients, 232 (39%) had EFW<10th and abnormal UA Doppler at last ultrasound prior to delivery. Of these, 110 (47%) underwent labor induction (mean GA 38 weeks), 98 (42%) had an elective pre-labor cesarean section (mean GA 34 weeks) and 24 (10%) had spontaneous onset of labor (mean GA 37 weeks). In the induction group (n=110), 25 (23%) had an emergency cesarean section and 15 (14%) had an operative vaginal delivery. This labor outcome did not differ significantly from patients who went into spontaneous labor. Table 1 demonstrates that labor induction was only considered in 16% of cases (16/100) prior to 37 weeks’ gestation compared to 71% (94/132) after 37 completed weeks (p<0.0001). Labor outcomes in the induction group prior to 37 weeks were comparable to those after 37 weeks’ gestation. NICU admission, APGAR scores and perinatal mortality rates did not differ in the respective groups. This analysis highlights that clinicians are influenced by gestational age when deciding about mode of delivery in the IUGR setting. Our study confirms that labor outcomes in nulliparous patients with IUGR are favorable and that labor induction could also be considered for IUGR pregnancies requiring delivery prior to 37 weeks gestation.Tabled 1 Open table in a new tab