A randomized trial of cerclage vs. 17 alpha-hydroxyprogesterone caproate for treatment of short cervix.

OBJECTIVE

To determine pregnancy outcome in patients with short cervix on transvaginal ultrasound between 16 and 24 weeks' gestation treated with McDonald cerclage compared to weekly intramuscular injections of 17 alpha-hydroxyprogesterone caproate (17OHP-C).

METHODS

From November 2003 through December 2006, asymptomatic, singleton pregnancies were screened with transvaginal ultrasound between 16-24 weeks' gestation. Patients with a cervical length (CL) < or =25 mm were offered enrollment. Patients were randomly assigned to treatment with McDonald cerclage or weekly intramuscular injections of 17OHP-C. The primary outcome was spontaneous preterm birth (PTB) prior to 35 weeks' gestation.

RESULTS

Seventy-nine patients met inclusion criteria; 42 were randomly assigned to the cerclage and 37 to 17OHP-C. Spontaneous PTB prior to 35 weeks' gestation occurred in 16/42 (38.1%) of the cerclage group and in 16/37 (43.2%) of the 17OHP-C group (relative risk, 1.14 95% CI, 0.67, 1.93). A post hoc analysis of patients with a prior PTB showed no difference in spontaneous PTB <35 weeks between groups. A similar analysis of patients with a CL< or =15 mm showed a reduction in spontaneous PTB <35 weeks in the cerclage group (relative risk 0.48, 0.24-0.97).

CONCLUSION

Women with CL < or =25 mm in the second-trimester appear to have similar risks of delivering prior to 35 weeks' gestation when treated with 17OHP-C or McDonald cerclage. However, cerclage may be more effective in preventing spontaneous PTB in women with CL< or =15 mm.