Effect of vaginal progesterone in tocolytic therapy during preterm labor in twin pregnancies: Secondary analysis of a placebo-controlled randomized trial.

AIM: Our aim was to investigate the effect of the prophylactic use of vaginal progesterone on the latency period from the initiation of tocolytic therapy to delivery in twin pregnancies with preterm labor.

METHODS: This study was a secondary analysis of a randomized, double-blind, placebo-controlled trial of twin pregnancies in mothers who were exposed to a 200 mg vaginal progesterone ovule or a placebo ovule daily from 18 to 34 weeks gestation. Patients who were administered tocolysis with Atosiban because of preterm labor were included. The latency from tocolysis to delivery, mean gestational age at delivery and the rates of delivery within 48 h and within seven days were compared between progesterone and placebo groups.

RESULTS: The analysis included 27 women in the progesterone group and 30 in the placebo group. The baseline characteristics were similar between the groups. Overall, there were no differences in the latency period to delivery (17.54 ± 13.54 days and 21.58 ± 13.52 days; P = 0.289), rates of delivery within 48 h (14.8% and 6.7%; P = 0.40) or within seven days (29.64% and 23.3%; P = 0.76) or mean gestational age at delivery (32.53 ± 3.33 and 34.13 ± 2.87; P = 0.08) between the progesterone and placebo groups, respectively.

CONCLUSIONS: Prophylactic use of 200 mg of vaginal progesterone does not influence the latency to delivery in women with twin pregnancies treated with tocolysis because of preterm labor.