The association between history of retained placenta and success rate of misoprostol treatment for early pregnancy failure

BACKGROUND: To date, the association between retained placenta and treatment success rate of misoprostol for early pregnancy failure has yet to be evaluated. The aim of this study was to evaluate this association and further investigated the connection between medical, clinical and sonographic parameters and treatment success. METHODS: We conducted a retrospective cohort study of women with early pregnancy failure treated with misoprostol from 2006 to 2021. The success rate of misoprostol treatment was compared between patients with history of retained placenta including women who underwent manual lysis of the placenta following delivery or patients who were found to have retained products of conception during their post-partum period (study group) and patients without such history (controls). Demographic, clinical, and sonographic characteristics as well as treatment outcomes were compared between the groups. RESULTS: A total of 271 women were included in the study (34 women in the study group compared to 237 women in the control group). Two-hundred and thirty-three women (86.0%) presented with missed abortion, and 38 (14.0%) with blighted ovum. Success rates of misoprostol treatment were 61.8% and 78.5% for the study and control groups, respectively (p = 0.032). Univariate analysis performed comparing successful vs. failed misoprostol treatment showed advanced age, gravidity, parity and gestational sac size (mm) on TVUS were associated with higher misoprostol treatment failure rate. Following a multivariate logistic regression model these variables did not reach statistical significance. CONCLUSION: Women who have an event of retained placenta following childbirth appear to have decreased success rate of treatment with misoprostol for early pregnancy failure. Larger studies are needed to confirm this finding.