Risk Factors of Retained Placenta in Siriraj Hospital
Pacharee Panpaprai MD*, Dittakarn Boriboonhirunsarn MD, MPH, PhD*
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital
Objective : To identify risk factors associated with retained placenta after vaginal delivery.
Design : Case-control study.
Materials and Methods : Medical records of 234 pregnant women whose gestational age > 28 weeks were
reviewed. Cases comprised of 78 women with retained placenta after vaginal delivery and controls comprised
of 156 women with spontaneous placental delivery. Associated risk factors were examined. Chi-square test
and logistic regression analysis were used for analysis of data.
Results : Cases were significantly older than controls (29.3 + 6.4 vs. 27.0 + 6.4 years respectively, p = 0.01).
Cases were likely more significant than controls to have a previous history of uterine curettage (20.5% vs.
6.4% respectively, p = 0.001) and premature rupture of membranes (35.9% vs. 22.4% respectively, p = 0.029).
Between the two groups, there were no differences in gestational age, parity, previous abortion, induction of
labor, oxytocin, and pethidine usage. Logistic regression analysis showed that independent risk factors for
retained placenta were age (adjusted OR 1.06, 95%CI 1.01-1.11), previous uterine curettage (adjusted OR
4.2, 95%CI 1.7-9.9), and PROM (adjusted OR 2.2, 95%CI 1.2-4.1).
Conclusion : Maternal age, previous uterine curettage, and PROM were independently associated with in-
creased risk of retained placenta. The condition should be aware of among pregnant women with such risk
factors.
Keywords : Retained placenta, Risk factors, Vaginal delivery
