Micronized Progesterone or Dydrogesterone? A Comparative Study on the Effects of Two Forms of Progesterone on Pregnancy Outcomes After Threatened Abortion

Background: A significant number of pregnancies are at risk of threatened abortion (TA). Different types of progesterone are used to treat TA. Objectives: In this study, the effects of 2 forms of progesterone on the continuation of pregnancy and TA-caused pregnancy outcomes were compared. Methods: A total of 190 women with a gestational age of 6 - 13 weeks presenting with uterine bleeding, closed cervix, and absence of fetal heart rate diagnosed by vaginal examination and ultrasound were allocated into 2 groups and treated with either (D) dydrogesterone (10 mg twice a day) or (M) micronized progesterone (200 mg, twice a day) for beyond 2 weeks after the cessation of uterine bleeding to ensure that bleeding would not recur. The participants were followed up and received prenatal care until the end of pregnancy. The outcomes of pregnancy were recorded and compared between the 2 groups. Results: The incidence of preeclampsia, gestational diabetes, cesarean section, intrauterine fetal death (IUFD), placenta previa, and abortion was not significantly different between the 2 groups. However, the prevalence of preterm labor and low birth weight (LBW) was significantly lower in M-treated women (P < 0.001 and P = 0.007, respectively). The baby’s weight and gestational age at delivery were significantly higher in the M group than in the D group (P < 0.001). No serious drug side effects were observed in the 2 groups throughout the study. Conclusions: The results of this study showed that the incidence of preterm labor and LBW was significantly lower in the patients treated with micronized progesterone than in patients treated with dydrogesterone; however, the prevalence of preeclampsia, gestational diabetes, cesarean section, IUFD, and abortion was not significantly different between the 2 groups.