Obstetric outcomes after medroxyprogesterone acetate treatment for early stage endometrial cancer or atypical endometrial hyperplasia: a single hospital-based study.

BACKGROUND: To investigate perinatal outcomes in pregnancy after high-dose medroxyprogesterone acetate (MPA) therapy for early stage endometrial cancer (EC) and atypical endometrial hyperplasia (AEH) and to determine whether pregnancy after MPA therapy is at a higher risk of placenta accreta. METHODS: Data of 51 pregnancies in 46 women who received MPA therapy for EC or AEH and delivered after 22 weeks of gestation at Keio University Hospital were reviewed. A retrospective matched case-control study was performed to determine the risk of placenta accreta in pregnancy after MPA therapy compared with singleton pregnancies without any history of maternal malignancy treatments. RESULTS: The incidence of placenta accreta was higher in the MPA group than in the control group (15.7 vs. 0%, p = 0.0058). However, no differences in other perinatal outcomes were observed between groups. While gestational weeks at delivery in the MPA group were later than those in the control group (p = 0.0058), no difference in the incidence of preterm delivery was recorded between groups. In the MPA therapy group, the number of patients who underwent ≥ 6 dilation and curettage (D&C) was higher in the placenta accreta group than in the non-placenta accreta group (50.0 vs. 14.0%, p = 0.018). Patients with ≥ 6 D&Cs demonstrated a 6.0-fold increased risk of placenta accreta (p = 0.043, 95% CI 1.05-34.1) than those receiving ≤ 3 D&Cs. CONCLUSION: Pregnancy after MPA therapy is associated with a high risk of placenta accreta. In cases in which the frequency of D&C is high, placenta accreta should be considered.