Prevalence, Outcome, and Predictors of Placenta Migration among Pregnant Women with Placenta Praevia in Enugu Nigeria

Abstract Background: Placenta praevia is one of the leading causes of obstetric haemorrhages and a major contributor to maternal and fetal morbidity and mortality. Although low-lying placentae are common during routine midtrimester anomaly scans, the incidence of placenta praevia at term remains low, probably due to placenta migration. It is important to follow-up pregnant women with low-lying placentae to identify the few whose placenta will remain in the lower segment and hence at risk of major obstetric haemorrhage. Aim: The objectives of this study were to determine the prevalence, predictors, and pregnancy outcome of low-lying placenta diagnosed in the midtrimester. Materials and Methods: The study was a cohort study with longitudinal follow-up of 416 pregnant women from the University of Nigeria Teaching Hospital, Enugu State University Teaching Hospital, and Mother of Christ Specialist Hospital who had an ultrasound diagnosis of low-lying placentae between 16 weeks and 20 weeks of gestation. Data analysis was performed using the Statistical Package for the Social Sciences (SPSS) version 22. P < 0.05 was considered statistically significant. Results: The prevalence of low-lying placenta at 20, 24, 28, 32, and 36 weeks of gestation was 51%, 41.3%, 22.3%, 12.7%, and 10.5%, respectively. 87.3% of those with low-lying placenta had normally situated placenta at term. Previous caesarean section and male gender were significant predictors of placenta praevia at delivery (P < 0.001 and P = 0.03, respectively). Conclusion: Despite the high prevalence of low-lying placenta before 20 weeks of gestation, only a few of these placentas remain low-lying at term. Previous caesarean section and male gender were significant predictors of placenta praevia at delivery. This study recommends a routine ultrasound scan in the second or third trimester for placenta localisation.