Background: To investigate the factors that may affect the time interval between induction and fetal expulsion in misoprostol-induced termination of second trimester pregnancy. Materials and Methods:A retrospective analysis of second-trimester pregnancies terminated in the second trimester between October 2008 and 2010 was performed. Induction was done by administration of 400 mcg intravaginal misoprostol. The correlation between the duration of abortion and maternal, fetal, and clinical features were statistically analyzed with multivariate regression analysis. Results: One hundred and seventy-five singleton pregnancies that met the inclusion criteria were evaluated. The average gestational age at the first induction was 18.3 weeks. The mean time interval between the first induction and expulsion was 37.2 ± 21.3 (range 3 to 160) hours. Fetal expulsion occurred significantly at a later gestational age and those with a higher blood glucose level at admission. However, no correlation could be established between the duration of abortion and the number of pregnancies, deliveries, age, hemoglobin levels or platelet count. Conclusions: Misoprostol is safe and effective in induction of abortion during second-trimester pregnancies. The induction-to-abortion interval is longer in patients with hyperglycemia and advanced gestational age. Prospective, randomized studies are necessary to better understand the factors influencing the duration of abortion.