Adjuvant Treatment with Oral Dydrogesterone in the Prevention of Preterm Labor: A Randomized, Double-Blinded, Placebo-Controlled Trial.

We conducted a double-blind, randomized, placebo-controlled clinical trial to evaluate the efficacy of oral dydrogesterone (DG) on maternal and neonatal consequences in the treatment of preterm labor. We included 100 nulliparous mothers (24-34 weeks) with normal pregnancy who had preterm labor pain. Participants who received magnesium sulfate were randomly assigned to the investigation group (DG 30 mg/day) or placebo group. Maternal and neonatal outcomes were compared between the two groups. Recurrent uterine contraction (UC) rates (92% vs. 88%, P = 0.862) and the incidence of preterm delivery (66% vs. 58%, P = 0.834) were not different in the DG and placebo groups. No significant differences were observed in terms of gestational age at delivery (33.5 ± 3.5 vs. 34.2 ± 3.2, P = 0.281), latency period (5.53 ± 2.29 days vs. 5.59 ± 2.57 days, P = 0.622), cervical dilation (1.82 ± 0.26 cm vs. 1.84 ± 0.29 cm, P = 0.281), and effacement (53 ± 4.47% vs. 57.21 ± 6.27%, P = 0.622) between the placebo and DG groups. The percentage of neonates with a 1-min Apgar score < 7 was higher in the placebo group compared with that of the DG group (12% vs. 0%, P = 0.0001). However, both groups were similar in the frequency of a 5-min Apgar score < 7. No differences in the term of adverse effects of medications were recorded. Our results showed that DG adjuvant to magnesium sulfate could not be effective in improving the incidence of preterm labor, rate of recurrent UC, latency period, pregnancy outcomes, and maternal and neonatal outcomes when compared with the placebo group.