However, in the preplanned subgroup analysis among women falling below the 25th percentile for cervical length (38 mm) at 16-22 weeks’ gestation, the rate of the composite of poor perinatal outcomes was 12% in the pessary group, significantly lower than the 29% in the usual care group (relative risk, 0.40). There was also a significant reduction in the risk of the component measure of death before discharge (RR, 0.14).
Additionally, in this subgroup of women, pessaries significantly prolonged the time to delivery (P = .01), leading to an older median gestational age (363/7 vs. 35 weeks in the usual care group) and reducing the risk of delivery before 32 weeks (RR, 0.49) and before 28 weeks (RR, 0.23).
"We are starting to look at the optimal cutoff [of cervical length for pessary placement] in post hoc analyses," Dr. Liem noted.
She disclosed no relevant financial conflicts.