A Comparative Study of Vaginal Misoprostol Moistened with Acetic Acid and Normal Saline in Second-trimester Pregnancy Termination: A Randomized Clinical Trial

Introduction: Second-trimester pregnancy termination with live fetuses is an important issue in obstetric practice since it is more challenging than first- and third-trimester pregnancy termination. The present study aimed to compare the effectiveness of vaginal misoprostol moistened with normal saline and acetic acid in second-trimester pregnancy termination.Methods: This clinical trial was conducted on 95 pregnant women with the gestational age of 14-26 weeks admitted for medical induced abortion. The subjects were randomly divided into two groups. The first group was administered with vaginal misoprostol moistened with acetic acid (n=47), and the second group received vaginal misoprostol moistened with normal saline (n=48). The abortion rate within the first 24 hours, induced abortion interval, length of hospital stay, and curettage and its complications were assessed in the study groups using statistical methods, and the P-value of less than 0.05 was considered significant.Results: Abortion within the first 24 hours occurred in 100% of the patients in the acetic acid group and 75% of the subjects in the normal saline group, and the difference was considered statistically significant (P<0.001). The mean time for fetal delivery was significantly lower in the acetic acid group (12.3±4.8) compared to the normal saline group (17.5±6.6) (P<0.001). In addition, the length of hospital stay was significantly lower in the acetic acid group compared to the normal saline group (P=0.008). The rate of abortion following the second dose of misoprostol was 46.8% in the acetic acid group and 20.8% in the normal saline group. However, no significant differences were observed in curettage and its complications between the groups.Conclusion: According to the results, high vaginal acidity was associated with the increased effectiveness of misoprostol in second-trimester pregnancy termination.