To Determine the Effects of Labor Induction on Maternal and Fetal Outcome in Postterm Pregnancies (41 Weeks Plus)

Abstract

Background: Pregnancies progressing postterm are associated with a higher perinatal morbidity and mortality rates than those delivered at term. In a United Kingdom study, the rate of stillbirth increased from 0.35 in 1000 live births in pregnancies of 37 weeks to 2.12 in 1000 live births in pregnancies of 43 weeks gestation. Morbidities associated with postterm births include an increased risk of fetal distress, intrauterine growth restriction, dysfunctional labor, shoulder dystocia, obstetric trauma (relative risk 1.09 - 1.68) and an increase in perinatal complications, such as aspiration of meconium and asphyxia, peripheral nerve injury, greenstick bone fractures, pneumonia and septicemia (adjusted odds ratio 1.4 - 2.0). Antenatal surveillance and induction of labor may decrease the risks of an adverse outcome. In a recent review of term and postterm pregnancies in Norway, we found that there were adverse outcomes associated with both postterm pregnancy and induction of labor independently. On comparison of the two, a randomized controlled trial showed no difference in their neonatal outcome, but demonstrated a reduction in the cesarean delivery rate when labor was induced at 41 weeks. Aim of the Work: The aim of this study was to determine the effect of labor induction on maternal and fetal outcome in postterm pregnancies. Subjects and Methods: This study was carried out on 150 pregnant women who had completed 41 weeks of gestation between Jun. 1, 2012 up to Dec. 31, 2012 at Department of Obstetrics & Gynecology, Faculty of Medicine, Benghazi University, and were scheduled for induction of labor after cardiotocography (CTG) and ultrasonography (USS) have been done and Bishop’s score assessed, to determine the effects of labor induction on maternal and fetal outcome in postterm pregnancies (41 weeks plus). Results: Regarding the relationship between a history of (H/O) postdatism and fetal distress, it was found that there was no significant relationship between them. There was a significant relationship between a history of macrosomia and fetal distress. There was a significant relationship between instrumental delivery and fetal distress. The majority of the fetal distress had an indication for Caesarean section (CS) (fetal distress (FD) and fetal distress meconium (FDM) more than those without fetal distress. All fetuses that had APGAR scores of 8 were distressed. There was a significant relationship between the APGAR score at 10 minutes with fetal distress. All fetuses that had meconium aspiration had fetal distress. There was a significant increase in the amount of oxytocin in unit in distressed cases than the non-distressed ones. The total duration of induction was also significantly increased in stressed fetuses than the non-stressed ones. There was a significant increase in the weight of distressed fetuses than the non-distressed. Conclusions: In conclusion, there was no difference in the neonatal outcome or mode of delivery for postterm pregnancies managed either by immediate induction of labor or expectantly with serial antenatal surveillance. The outcomes were generally good, and neonatal morbidity, cesarean section, and operative vaginal delivery rates were low. If pregnancy is uncomplicated and continued surveillance is possible, women’s own wishes may guide the decision to induce or monitor a pregnancy beyond 41 weeks.