Evaluation of the efficacy of vaginal progesterone in preventing preterm birth after abdominal trachelectomy

•Pregnant women after abdominal trachelectomy (AT) were high risk at preterm birth.•Vaginal progesterone (VP) did not prevent preterm birth in women after AT.•Presence of uterine cervix is essential for preventive effects of VP on preterm birth. To determine whether vaginal progesterone (VP) reduces the rate of preterm birth in pregnant women after abdominal trachelectomy (AT) for early-stage cervical cancer This is an interventional study with a historical cohort. For the interventional study participants who had singleton pregnancies after AT between October 2016 and September 2020, the administration of vaginal progesterone was started between 16+ and 19+6 weeks of gestation and discontinued at 34 weeks of gestation or at the time of delivery, rupture of membranes, or massive uterine bleeding. We investigated obstetric and neonatal outcomes among the study participants and compared them with outcomes of the historical control group participants, included women with singleton pregnancies after AT who were managed without VP at our institution between January 2007 and September 2016, using Fisher’s exact test and the Mann–Whitney U test The main outcomes were the gestational age at delivery and incidence of preterm birth before 37 weeks and 34 weeks of gestation. Twelve pregnancies in ten women were included in the VP group. In contrast, 19 pregnancies in 17 women were included in the historical control group. The incidence of preterm birth at