Objective: Retained placenta is a serious complication of vaginal birth. The ability to predict retained placenta may have positive effect on timely management. We aimed to evaluate the maternal and obstetric risk factors associated with retained placenta after singleton live vaginal birth Methods: A retrospective cohort of women who had retained placenta after singleton live vaginal birth ≥ 24 weeks, compared in 1:2 ratio with women who had normal vaginal delivery without complications. Study and control group were matched for maternal age, gestational age and parity. Multivariate regression analysis was performed to evaluate the potential risk factors for retained placenta including maternal and obstetrical characteristics Results: Fifteen thousand two hundred sixty women underwent vaginal delivery at our medical center between 2015-2022. One hundred seventy women (1.1%) were diagnosed with retained placenta. Ninety-nine women (0.65%) who met the inclusion criteria, were matched with 198 women (1.3%) as controls. Multivariate logistic regression revealed various potential risk factors not previously described as associated with retained placenta including: IVF pregnancy (OR 3.8, 95% CI [1.3- 11.7], P 0.018), preeclampsia (OR 4.5, 95% CI[1.1- 17.5 ],P 0.0315), women with large for gestational age fetus (OR 28.2, 95% CI [5.4- 148.5], P 0.0298),labor Induction (OR 21.8, 95%CI [5.5- 86.8],P <0.001), vacuum assisted vaginal delivery (OR 2.3 .95% CI [1.2- 4.5], P 0.011), and Duration of second stage > 3 hours (OR 3.9,95%CI [1- 15.1], P <0.001) Conclusion: Our study highlights unreported risk factors associated with retained placenta such as macrosomia , in vitro fertilization and endometriosis. This emphasis on early risk identification and the exploration of possible preventive measures holds promise for enhancing antenatal care practices, ultimately improving outcomes for both mothers and infants .
