Outcomes of Induction of Labor Versus Expectant Management in Low-risk Pregnancies at 39-41weeks in Pumwani Maternity Hospital, 2020: a Prospective Cohort Study

Abstract

Introduction: The Royal College of Obstetrician Gynecologists (RCOG), American College of Obstetrician Gynecologists (ACOG) and the WHO recommend induction of labor for pregnancies at 41 weeks gestation and beyond for improving maternal and neonatal outcomes and not below 39 weeks where there is no clear medical indication. A Randomized trial of Induction of labor (IOL) versus Expectant management (EM) in 2018 in the United States reported reduction in caesarian section (CS) rates and the risk of adverse perinatal outcomes among low-risk nulliparous pregnancies at 39 weeks gestation. There are no comparable local or regional studies to inform the management of low-risk pregnancies between 39-41 weeks gestation in resource constrained settings. Objective To determine the risk of adverse obstetric and early neonatal outcomes of low-risk pregnancies at 39-41weeks gestation undergoing induction of labor compared to expectant management at PMH. Methodology: The study design was a prospective cohort study carried out at Pumwani Maternity Hospital, the largest maternity hospital in Sub-Saharan Africa. Low-risk consenting pregnant women at 39-41 weeks gestation were enrolled. The primary outcome was the incidence of operative delivery while the secondary outcomes included composite adverse maternal and neonatal outcomes and were compared between those induced and those expectantly managed. Data was collected using a structured pretested questionnaire from interviews as well as patient files. Data was cleaned and exported in a Statistical Package (SPSS – Version 24.0). Descriptive statistics were used to describe socio-demographic characteristics and differences between the two groups. Cross-tabulations were then be used to identify risk factors. X2 and Fisher exact tests were used to evaluate the differences in distributions of socio-demographic and labor-related characteristics of the two groups and their impact on the mode of delivery. Relative Risk were calculated, comparing IOL at 39-41 weeks with EM while utilizing the incidence of operative delivery, adverse maternal and neonatal outcomes. Multivariable logistic regression was done to test association and control for confounders. A P value < 0.05 was considered to be statistically significant. Results: Between August and November 2020, 252 pregnant women were screened and 224 were enrolled. A total of 107 pregnant women underwent IOL while 117 underwent EM. Sociodemographic and obstetric characteristics were comparable between the two groups. IOL was also associated with lower incidence of CS (15% vs 16.2% P=0.79) although this was not statistically significant. There was a significantly higher incidence of non-reassuring fetal status among those who underwent EM (12.5% vs 47.4%, P=0.002). The incidence of composite adverse maternal and neonatal outcomes was comparable between IOL and EM (14.9% vs 23.1%, P=0.123 and 23.4%vs 19.6%, P=0.51). The need for resuscitation/respiratory support was significantly higher with IOL compared to EM (8.4%vs 1.7%, P= 0.02) Conclusion: Among low-risk women undergoing IOL vs EM, the incidence of CS and composite adverse maternal and neonatal outcomes were comparable between the two groups. However, IOL was associated with a higher need for resuscitation or respiratory support Recommendations: Either IOL or EM is recommended among low-risk pregnant women between 39-41 weeks. In both cases, keen follow up is crucial to achieving good obstetric outcomes. A randomized control trial and further studies assessing the level of satisfaction, quality of intrapartum care of low-risk pregnancies between 39-41 weeks gestation are recommended. Evidence relating to cervical priming and duration from onset of labor to delivery may provide for plausible explanation for the perineal tears and adverse fetal events found in this study