Placenta praevia and the risk of adverse outcomes during second trimester abortion: A retrospective cohort study.

BACKGROUND: There are few reports in the literature of the risks associated with second trimester abortion in women with placenta praevia (PP). We hypothesise that PP increases the risk of complications.

AIMS: We sought to determine if PP is associated with a higher risk of blood loss and blood transfusion at the time of dilation and evacuation (D&E).

MATERIALS AND METHODS: The records of 612 consecutive women undergoing abortion at 15-24 weeks of gestation were reviewed. Participant characteristics, need for blood transfusion, estimated blood loss (EBL) during the abortion and other complications were compared between women with and without ultrasound-documented PP.

RESULTS: Eighty-seven of 612 (14.2%, 95% CI 11.5-17.2%) women had ultrasound-documented PP. The rate of blood transfusion was 3.4 and 1.3% in the group with PP and without PP, respectively (adjusted relative risk (RR = 2.8, 95% CI 0.7-11.3). An estimated blood loss of 500 cc or greater during the D&E procedure was observed in 12.6% of women in the PP group compared with 4.2% of women in the group without PP (adjusted RR 3.1, 95% CI 1.4-6.8, P = 0.004).

CONCLUSIONS: Second-trimester abortion in women with PP is associated with a higher risk of blood loss of 500 cc or greater. Our study represents a larger sample size of patients with PP undergoing second-trimester abortion than previously reported in the literature. Women with PP may have a higher estimated blood loss and may require access to blood transfusion.