Maintenance tocolysis with oral micronized progesterone for prevention of preterm birth after arrested preterm labor

To evaluate the efficacy of maintenance therapy with oral micronized progesterone (OMP) for prolongation of pregnancy in cases of arrested preterm labor.

Ninety women at 24-34weeks of singleton pregnancy with intact membranes and arrested preterm labor were randomly allocated to receive OMP (n=45) or placebo (n=45) daily until 37weeks or delivery, whichever was earlier. Outcome parameters were compared using Student t test, χ(2) test, Fisher exact test, and log-rank χ(2) test.

OMP significantly prolonged the latency period (33.29±22.16 vs 23.07±15.42days; P=0.013). Log-rank analysis revealed a significant difference in mean time to delivery between the 2 groups (P=0.014). There were significantly fewer preterm births (33% vs 58%; P=0.034) and low birth weight neonates (37% vs 64%; P=0.017), and significantly higher mean birth weight (2.44±0.58 vs 2.14±0.47kg; P=0.009) in the OMP group. Perinatal outcomes and adverse effects were similar in the 2 groups.

Maintenance tocolysis with OMP significantly prolonged pregnancy and decreased the number of preterm births. Clinical Trial Registry of India: CTRI/2011/10/002043.