Comparison of Placenta Previa and Placenta Accreta Spectrum Disorder Following Previous Cesarean Section between Women with a Short and Normal Interpregnancy Interval

Abstract

Objectives. The aim of this study is to determine the effect of interpregnancy interval (IPI) on the incidence of placenta previa and placenta accreta spectrum disorders in women with a previous cesarean section. Methods. A prospective cohort three-center study involving parturients who had previous cesarean section was conducted. Participants were included if pregnancy has lasted up to 34 weeks. Parturients with co-existing uterine fibroids, multiple gestations, premature rupture of membranes, and those with prior postcesarean delivery wound infection were excluded. The eligible women recruited were distributed into two groups, namely, short (<18 months) and normal (18–36 months) IPI. The outcome measures were incidences of placenta previa and placenta accreta spectrum disorder and factors associated with the occurrence of placenta previa. A univariate analysis was performed using the chi-square test or Mann–Whitney U test, wherever appropriate, to examine the significance of the differences in clinical variables. Results. A total of 248 women met the inclusion criteria. The incidence of placenta previa by ultrasound was 8.9% and 4.0% for short and normal IPI (odds ratios = 2.32; 95% confidence intervals = 0.78–6.88; $p=0.13$ ), respectively. The incidence of placenta accreta spectrum disorder was 1.6% and 0.8% for short and normal IPI (odds ratios = 2.02; 95% confidence intervals = 0.18–22.13; $p=0.57$ ), respectively. The only observed significant difference between the clinical variables and placenta previa is the number of cesarean sections ( $p=0.02$ ) in women with short IPI. Conclusion. A short interpregnancy interval does not significantly affect the incidence of placenta previa and placenta accreta spectrum disorder following a cesarean section. There is a need for further study with large numbers to corroborate these findings in low- and middle-income settings.