Risk and prediction of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin before 34 weeks

Abstract

Objective: To assess the timing and risk factors of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin (APHUO) before 34 weeks of gestation, and to formulate a clinical management protocol.

Methods: A retrospective study involving singleton pregnancies with APHUO occurring before the 34th week of gestation was performed over a 4-year period at a university teaching hospital.

Results: Seventy-five cases were identified. Fifty-nine (78.7%) did not have any associated uterine contractions, 74.7 and 90.7% of the cases were classified as having mild bleeding according to history and physical examination, respectively. The number of cases delivering before 37 weeks of gestation and before 34 weeks were 28 (37.3%) and 22 (29.3%), respectively. Eighteen cases (24%) delivered within the first week of APHUO, and 4 (5.3%) within the first day. The number of cases delivering within the first week was significantly higher when there were uterine contractions (62.5 vs. 13.6%, p < 0.001). The severity of bleeding was not shown to be related to the time of delivery.

Conclusion: APHUO that occurs before 34 weeks is associated with a high risk of preterm delivery before 34 weeks (29.3%). The chance of delivery within the first week is 62.5% when there are coexisting uterine contractions. Even if contractions are absent, the risk is still high (13.6%) and persists beyond the first week. We suggest that this group of patients should be managed with a course of steroid injection and hospitalization for 4 days.