Objective: We aimed to determine the incidence and risk factors for retained placenta immediately after vaginal delivery in a single, university-affiliated tertiary center.
Methods: A case-control study. Women who delivered vaginally and diagnosed with suspected retained placenta were compared to control group of women with spontaneous vaginal delivery with spontaneous non-complicated placental separation between the years 2007 and 2012. Eligibility was limited to singleton fetuses in vertex presentation with no history of more than one cesarean section, stillbirth or major fetal anomaly.
Results: Overall, 33,925 women delivered vaginally, of them, 491 (1.4%) underwent revision of uterine cavity due to suspected retained placenta. Women with retained placenta were characterized by a higher rate of previous cesarean section (OR 1.71, 95% CI 1.23-2.36), previous abortions, lower parity (OR 0.79, 95% CI 0.68-0.91), lower gestational age at delivery. Hypertensive disorders, oligohydramnios and labor and delivery interventions as induction of labor (OR 1.84, 95% CI 1.30-2.59), neuro-axial analgesia (OR 1.60, 95% CI 1.27-2.00) and vacuum delivery (OR 1.89, 95% CI 1.48-2.41) were independently associated with uterine revision for retained placenta.
Conclusion: Risk factors for manual revision due to retained placenta can be recognized. This data should be taken into consideration in the assessment of women immediately after delivery.
Keywords: Delivery; hemorrhage; retained placenta; risk factor.