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

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.