Maternal and fetal outcomes of pregnancies beyond 40 weeks of gestation at a tertiary care hospital in Port Harcourt, Nigeria

Abstract

Background: Pregnancy beyond 40 weeks is a frequent dilemma faced by obstetricians as the risk to the mother and the fetus increases with advancing gestational age. This risk becomes more evident as the pregnancy goes beyond 42 weeks. Objective: This study aimed to determine the prevalence of postdate pregnancy and to evaluate the maternal and fetal outcomes at a tertiary care hospital.Methods: A retrospective study was conducted over a two-year period from 1st May 2021 to 30th April 2023. The study population were women who were delivered after 40 weeks of gestation. Information was extracted from the hospital records using a proforma. Data were analyzed with SPSS for Windows version 23 and presented using frequency tables, as number and percentages. Statistical analysis was performed using the Chi-square test or Fisher’s exact test as appropriate, and the level of significance was set at P value of 0.05. Independent variables were analyzed using bivariate analysis, and the variables with an association were fitted into a multivariate logistic regression analysis.Results: The prevalence of postdate pregnancy was 9.0%. Vaginal delivery occurred in 53.2% whereas 46.8% required caesarean delivery, the most common indication being cephalopelvic disproportion 53.1%, and the proportion increased with increase in gestational age. The stillbirth rate was 3.2% and the perinatal asphyxia rate was 7.6%, both increased with increasing gestational age. The gestational age ≥42 weeks was associated with a four-fold increased risk of caesarean delivery and seven-fold increased risk of stillbirth.Conclusion: Postdate pregnancy was significantly associated with poor maternal outcome in the form of increased caesarean delivery rates, primarily due to cephalopelvic disproportion and fetal distress. Perinatal mortality was high, and fetal complications, especially perinatal asphyxia resulted in higher rate of admission to neonatal intensive care unit.