Abstract
Background. The efficacy of medical treatment of first trimester miscarriages may depend on the regimen used, the definition of success, clinical symptoms, and, possibly, on the ultrasonographic findings. Our primary aim was to assess if a single dose of misoprostol could reduce the number of surgical interventions in early pregnancy failure, and to compare efficacy in different ultrasonographically-defined subgroups. Methods. A retrospective review of 355 consecutive patients treated for a first trimester miscarriage with a single dose of vaginal misoprostol (400 µg), followed by vaginal ultrasonography after either 1, 2 or 3 days. Treatment was successful if a complete abortion was diagnosed at follow-up. The women were divided into 4 ultrasonographically-defined groups: missed abortion with a crown rump length (CRL) ≥6 mm (Group A1) or CRL <6 mm (Group A2), anembryonic gestation with gestational sac ≥18 mm (Group B1) or <18 mm (Group B2). Results. The overall success rate was 39.2% (139/355). The regimen was more efficacious in Group A2 (50%) and less efficacious in Group B1 (26.6%) than in the other groups. The success rates were lower 1 day after treatment (30.2%) compared to days 2 and 3 (43.6%; p<0.05), and the difference was largest in Group B1 (12.9 versus 35.4%; p<0.05). Conclusions. Single dose misoprostol reduced the number of surgical interventions. The success rates of medically-treated first trimester miscarriages varied according to the ultrasonographic definitions of pregnancy failure, time of assessment, and the criteria for success.