Objective: To evaluate the causes of MTM and their impact on subsequent pregnancies.
Material and methods: A retrospective single-center cohort study of all pregnancies with a second-trimester pregnancy loss between 14 weeks and 21 weeks + 6 days gestation, excluding terminations of pregnancy (TOP) and in utero fetal deaths. Predefined criteria were used to allocate cases to one of 6 primary etiologic diagnoses: cervical insufficiency, chorioamnionitis, placental anomalies, fetal anomalies, iatrogenic causes, or abdominal trauma.
Results: Among 578 mid-trimester fetal losses, 175 were MTM, a prevalence of 5.7 per 1000 live births in the center. The suspected primary cause was cervical insufficiency in 76 cases (43.4%), chorioamnionitis in 59 (33.7%), placental anomalies or preterm premature rupture of membranes in 26 (14.8%), iatrogenic in 8 (4.6%), trauma in 3 (1.7%), and undetermined in 3 cases (1.7%). A subsequent pregnancy beyond 14 WG was recorded for 78 patients. Recurrent MTM occurred in 21.8% and preterm deliveries in 14.1% ; 13% of patients without evidence of cervical insufficiency in the index pregnancy required emergency cerclage.
Conclusion: Cervical insufficiency was the leading cause of MTM, with a high risk of recurrent MTM or preterm birth, thus prophylactic cerclage or cervical length measurements should be considered for subsequent pregnancies.
Keywords: Mid-trimester miscarriage; cerclage; cervical insufficiency; pregnancy loss; preterm delivery; preterm premature rupture of membranes.