Prognostic factors for predicting preterm birth after a first bleeding episode for patients with placenta previa

Overview & Synopsis

Introduction: placenta previa, found in 0.5% of pregnancies, is responsible for maternal and neonatal morbidity. The main maternal complication is antepartum genital bleeding. It increases the risk of preterm birth. Our objective was to identify prognostic factors of preterm delivery after a first episode of bleeding in placenta previa. This, in order to help the therapeutic management of these patients, especially to define when to do the antenatal corticosteroid because their effect diminishes beyond the 7th day after the treatment and is effectless beyond the 15th day. Study design: this was a multicenter retrospective study. Our population was women with placenta previa between 24 and 36 weeks of gestation, who had a first episode of bleeding. We selected 11 variables that could be associated with preterm birth. The primary outcome was delivery within 7 days after a first episode of bleeding and the secondary outcome was delivery within 15 days. Results: two hundred forty patients were included between January 1, 2007 and December 31, 2012. We found only one prognostic factor from univariate analysis of preterm delivery within 7 days after a first bleeding episode: the cervical length ≤25mm (OR = 2.78 (95% CI 1.15-6.73), p 0.02). This factor is also found after a multivariate analysis (OR = 2.77 (95% CI 1.13-6.81), p 0.03). However, we found no prognostic factors for preterm delivery within 15 days. Conclusion: only a decrease in cervical length ≤25mm is associated with preterm delivery after a bleeding episode for patients with placenta previa. Preterm birth is therefore difficult to predict and the right time for corticosteroids remains at the discretion of practitioners.