Prospective risk of abruptio placentae

The aim of this study was to better characterize the nature of abruptio placentae (AP) with regard to the timing of onset.

Prevalence and prospective risk of AP according to gestational week (GW) were determined among 293,899 women who gave birth to singleton infants at and after GW 30. The prospective risk of AP at gestational week N was defined as the number of all women who experienced an AP at ≥GW N divided by the number of all women who gave birth at ≥GW N.

AP developed in 2649 (0.90%) women. The prevalence of AP (6.7% among women who gave birth at GW 30-33) sharply decreased with advancing GW at delivery to 0.9% for GW 37 and 0.1% for ≥GW 42. The highest prospective risk of AP, 9 per 1000 women at GW 30, decreased linearly with advancing gestation to 1 per 1000 women at ≥GW 42. AP accounted for 4.7% (1591/33,725) of all preterm births at GW <37, while prevalence of AP was 0.41% (1058/260,174) among term births. Preterm AP accounted for 60.1% (1591/2649) of all AP.

Our figures indicate that AP is more common in preterm births than in term birth and may be helpful for better understanding the epidemiology of this condition.