Study of Placentation in Previous Caesarean Section: A Cross-Sectional Analysis of Placental Location and Morbidity

Objective: To determine the patterns of placental location and the frequency of abnormal placentation in women with prior cesarean section (CS), and to correlate these findings with maternal and perinatal outcomes.

Methods: A cross-sectional study was conducted on 110 pregnant women with at least one previous CS and gestational age ≥34 weeks. All participants underwent detailed ultrasonographic evaluation for placental localization, edge-to-os distance (EOD), and sonographic features of placenta accreta spectrum (PAS). Intraoperative findings and maternal-fetal outcomes were recorded and correlated with placental location relative to the uterine scar.

Results: Among 110 women with previous CS, low-lying placenta or placenta previa was identified in 26.4% (n=29). The frequency of PAS disorders was 12.7% (n=14), with the risk increasing progressively with the number of prior CS: 8.5% in women with one previous CS, 22.2% in those with two, and 42.9% in women with three or more previous CS (p<0.01). Anterior placental location was associated with significantly higher odds of PAS compared to posterior location (OR 4.2, 95% CI 1.8-9.7). Edge-to-os distance showed an inverse correlation with placental adherence (r=-0.42, p=0.002). Women with abnormal placentation had significantly higher rates of postpartum hemorrhage (48.3% vs. 11.1%, p<0.001), blood transfusion (34.5% vs. 6.2%, p<0.001), and preterm delivery (41.4% vs. 18.5%, p=0.01).

Conclusion: Prior cesarean section significantly increases the risk of abnormal placentation in subsequent pregnancies, with the risk escalating with each additional CS. Anterior placental location and reduced edge-to-os distance are important sonographic predictors of placental adherence. These findings support targeted surveillance protocols for high-risk women to optimize maternal outcomes.