Cervical sonography in pregnant women with a prior cone biopsy or loop electrosurgical excision procedure.

Objectives: To determine if pregnant women with a prior cone biopsy or loop electrosurgical excision procedure (LEEP) have a shorter midtrimester cervical length than do matched controls without a history of cervical surgery.

Methods: Eighty-five pregnant women with a singleton gestation and previous cone biopsy or LEEP and 85 controls matched by age (± 5 years), race, gestational age (± 2 weeks), and number of prior vaginal deliveries underwent a single transvaginal cervical sonographic scan at 15-22 weeks' gestation. No patient had a cerclage in either group.

Results: Mean cervical length was significantly shorter in the cone biopsy/LEEP group (3.3 vs. 3.9 cm, P < 0.001), with no significant difference in the proportion of cervical lengths less than 2.5 cm (5.9 vs. 2.4%). Gestational age at delivery was slightly but significantly lower in the cone biopsy/LEEP group (38.1 vs. 39.1 weeks, P = 0.005) than in the control group, with a higher proportion of women delivering late preterm and very preterm in the cone biopsy/LEEP group. However, no woman with a prior cone biopsy/LEEP experienced a midtrimester loss suggestive of cervical insufficiency, and no patient with a cervical length less than 2.5 cm delivered before 34 weeks' gestation.

Conclusions: Midtrimester cervical length in women with a previous cone biopsy or LEEP is significantly shorter than in those without prior cervical surgery. Based on the low frequency of a short cervix or midtrimester loss in women with prior excisional surgery, the routine use of midtrimester cervical sonography in such women is not supported.