Cerclage for the prevention of preterm birth in high risk women receiving intramuscular 17-α-hydroxyprogesterone caproate.

OBJECTIVE: To assess cerclage benefit in women with short cervix also receiving 17-α-hydroxyprogesterone caproate (17P) to prevent recurrent preterm birth (PTB).

METHODS: Secondary analysis of a multicenter trial of ultrasound-indicated cerclage for shortened cervical length (CL). Women with prior spontaneous PTB at 16-33 6/7 weeks, singleton gestation and CL < 25 mm between 16 and 22 6/7 weeks were counseled on use of 17P and randomized to cerclage or no cerclage. Outcomes of women who received 17P were analyzed by randomization group. Primary outcome was PTB < 35 weeks.

RESULTS: 99 women received 17P: 47 cerclage; 52 no cerclage. Rates of PTB < 35 weeks were similar, 30% for cerclage and 38% for no cerclage (aOR 0.64 (0.27-1.52)). In women with CL < 15 mm, PTB < 35 weeks was reduced for the cerclage group (17% vs. 75%, p = 0.02). However, this difference was nullified after controlling for total progesterone doses received (p = 0.40).

CONCLUSIONS: Cerclage was shown not to offer additional benefit for the prevention of recurrent PTB in women with short CL < 25 mm receiving 17P, but the sample size is insufficient for a definite conclusion given the 36% nonsignificant decrease in the odds of PTB < 35 weeks. Cerclage may further offer substantial benefit to women with very short CL < 15 mm and further study is needed.