Placenta praevia: Incidence, risk factors and outcome

Purpose: Placenta praevia is frequently associated with severe maternal bleeding leading to an increased risk for adverse outcome of mother and infant. Aim of this study was to evaluate the incidence, potential risk factors and the respective outcomes of pregnancies with placenta praevia.

Material and methods: We performed a retrospective study on women diagnosed with placenta praevia in 10 styrian hospitals between 1993 – 2012. Differences between women with major placenta praevia (complete or partial placenta praevia) and minor placenta praevia (marginal placenta praevia or low-lying placenta) were evaluated.

Results: 328 patients with placenta praevia were identified. The overall incidence of Placenta praevia was 0.44%, rates increased from 0.36% to 0.54%. The most important risk factors included prior uterine surgery (49%), advanced maternal age (24.7%> 35a), multiparity (57%), prior caesarean delivery (22.8%), recurrent abortions (22.8%), prior placenta praevia (10.8%) and smoking (6%). Maternal morbidity was high (antepartum bleeding 42.3%, postpartum hemorrhage 7.1%, maternal anemia 30%, comorbid abnormal placentation 4%, and hysterectomy 5.2%); however there was no maternal death. Neonatal complications including preterm birth (54.9%), low birth weight (< 2500 g: 35.6%), apgar-score after 5 minutes < 7 (5.8%) and fetal mortality (1.5%). There were no differences between women with minor placenta praevia and major placenta praevia regarding risk factors and maternal outcome. Women with major placenta praevia showed significant higher incidence of preterm delivery (OR = 6.04, CI 3.27 – 11.15, p < 0.01) birth weight < 2500 g (OR = 3.82, CI 2.05 – 7.11, p < 0.01) and apgar-score after 5 minutes < 7 (OR = 6.39, CI 1.35 – 30.35, p < 0.01).

Conclusion: The incidence of placenta praevia was 0.44% and increased, equally to caesarean rates and maternal age, about 50%. Placenta praevia is associated with adverse maternal (34.15%) and neonatal (60.06%) outcome. Therefore an early detection of risk factors would be important to improve maternal and fetal outcome.