Does indomethacin prevent preterm birth in women with cervical dilatation in the second trimester?

We sought to estimate the effect of indomethacin on duration of pregnancy in women with dilated cervix between 14 0/7 to 25 6/7 weeks. Demographics, risk factors, and outcomes were compared in women 14 6/7 to 25 6/7 weeks with a dilated cervix ≥ 1 cm who received indomethacin versus no indomethacin therapy, stratified for cerclage. Primary outcome was interval from presentation until delivery. Of 222 singleton gestations, 68 (31%) received indomethacin. In unadjusted and adjusted analyses, no significant differences were observed in interval from presentation to delivery and preterm birth < 28, < 32, or < 35 weeks comparing the indomethacin and no indomethacin groups, even after stratification for cerclage. In multivariate logistic regression analysis limited to women receiving cerclage, preterm birth < 32 weeks (odds ratio 0.56, 95% confidence interval 0.26, 1.25) and < 35 weeks (odds ratio 0.52, 95% confidence interval 0.23, 1.14) suggested a possible but not significant benefit for indomethacin use. Indomethacin therapy in women with dilated cervix at 14 0/7 to 25 6/7 weeks, regardless of cerclage or not, had no effect on pregnancy outcomes.