P-351 Medical treatment for missed abortion- difference in gestational age based on menstrual dating and on ultrasound criteria, and the correlation to failure

Abstract

Abstract Study question Does the difference in gestational age based on menstrual dating and on ultrasound criteria correlate with failure rate of medical treatment in missed abortions? Summary answer In missed abortions, the difference in gestational age based on menstrual dating and on ultrasound is inversely correlated with failure rate of medical treatment. What is known already A number of factors have been reported as predictors for Misoprostol treatment failure, including assisted reproductive treatment, primigravity, and vaginal bleeding prior to treatment. Increased rates of failure with medical management were also reported with delaying treatment after diagnosis. Study design, size, duration This was a retrospective cohort study. Overall, 778 patients who underwent medical treatment with Misoprostol for missed abortion at our institute, between 07/2015 and 12/2020 were included. Participants/materials, setting, methods Inclusion criteria were either anembryonic gestation or embryonic death, as long as pregnancy age, as measured by transvaginal sonography , correlated with 12 weeks gestation or less. Exclusion criteria included incomplete or septic abortions, multiple pregnancies, and cases that had either irregular period, missing data, or were lost to follow up. The primary outcome was treatment failure, defined as any need for surgical intervention (elective or emergency Dilation & curettage, or operative hysteroscopy). Main results and the role of chance Five hundred and eighty two patients (74.9%) had successful medical treatment, while 196 (25.1%) required surgical intervention. The gestational age based on menstrual dating and on ultrasound difference (in weeks) was 2.6±1.4 in the success group and 3.1±1.6 in the failure group (p < 0.001). On multivariant regression analysis, gestational age based on menstrual dating and on ultrasound difference was found to be independently correlated with treatment failure (aOR=1.24, CI 95% (1.01-1.51), p = 0.03). Limitations, reasons for caution We did not analyze long term consequences, such as the amount of bleeding, and time to future fertility. Moreover, patients who were treated at our institute may have been diagnosed and treated for treatment failure in neighboring hospitals and hence lost to follow-up. Wider implications of the findings The current study has shown that the difference between gestational age based on menstrual dating and on ultrasound is directly corelated with medical treatment failure. This data should be taken into account when counseling patients regarding the optimal treatment for first trimester missed abortion. Trial registration number not applicable