Factors influencing the abortion interval of second trimester pregnancy termination using misoprostol

To determine the factors influencing the abortion interval (AI) for medical termination of second-trimester pregnancy using misoprostol.

All patients who were admitted for second-trimester pregnancy termination between January 2008 and August 2013 were reviewed. Those who received either 200 μg or 400 μg of priming vaginal misoprostol, followed by 200 μg of misoprostol orally at 6-hour intervals were enrolled.

In a total of 101 patients, delivery occurred within 24 hours of commencement in 62 patients (61%) and within 48 hours in 84 patients (83%), and the median AI was 16.5 hours. One patient (1%) failed to deliver. The remaining 100 fetuses were delivered successfully, and the median AI was 16.3 hours. Higher parity [hazard ratio (HR) = 1.28, p = 0.04], the presence of intrauterine fetal demise (HR = 2.66, p = 0.003), and the presence of premature preterm rupture of membranes (HR = 4.51, p = 0.003) were associated with shorter AI. Additionally, all women with premature preterm rupture of membranes delivered successfully within 12 hours; higher parity (odds ratio = 2.12, p = 0.01) and lower fetal birth body weight (odds ratio = 0.992, p = 0.01) were associated with successful delivery within 12 hours. There was no significant difference in AI in the groups that received different doses of priming vaginal misoprostol (200 μg vs. 400 μg).

Higher parity, intrauterine fetal demise, and preterm premature rupture of membranes were associated with shorter AI. The regimen of 200 μg oral misoprostol at 6-hour intervals following a 200 μg or 400 μg priming vaginal dose is feasible and efficacious for second trimester pregnancy termination.