Evaluating the safety of labour in women with a placental edge 11 to 20 mm from the internal cervical Os.

Objective: The purpose of this study was to evaluate pregnancy outcomes in a cohort of women with a placental edge between 11 and 20 mm from the internal cervical os, and to determine the likelihood of a successful vaginal delivery when trial of labour is attempted in these women.

Methods: We carried out a prospective observational study of women with singleton pregnancies and a placental edge between 11 and 20 mm from the internal cervical os (identified by transvaginal sonography) who underwent a trial of labour.

Results: Fourteen women with the above characteristics underwent a trial of labour during the study period. The mean interval (± SD) from ultrasound to delivery was 17.2 ± 9.6 days. Thirteen women (92.9%) delivered vaginally with no complications, and only one woman (7.1%) required an emergency Caesarean section for intrapartum bleeding. The risks of antepartum and postpartum hemorrhage were 21.4% and 14.3%, respectively.

Conclusion: Having a placental edge more than 10 mm from the internal os, measured by transvaginal sonography near term, justifies allowing a trial of labour and carries a low risk of subsequent obstetrical hemorrhage.