Although double cervix is often considered to indicate uterus didelphys, it may be challenging to determine the true associated anomaly as double cervix occurs with other müllerian anomalies. Our purpose is to report the frequency of uterine müllerian anomalies that occur with a double cervix and identify imaging or clinical criteria to help classify the associated anomaly.

After institutional review board approval, an electronic search was performed to identify patients with double cervix and pelvic magnetic resonance imaging (MRI) between 1976-2010 (using International Statistical Classification of Diseases and Related Health Problems, Edition 9 and Hospital International Classification of Diseases Adapted codes). MRIs were reviewed to classify the müllerian anomaly. Clinical characteristics including cervical canal thickness, intercervical distance and orientation were recorded. Kruskal-Wallis and χ² tests were used to test for differences in patient and imaging characteristics across müllerian anomalies.

There were 64 patients who met inclusion criteria: 32 (50%) septate uterus, 27 (42%) uterus didelphys and 5 (8%) bicornuate uterus. Cervical canal divergence was present in 34% (11/32) with septate uterus, 26% (7/27) with uterus didelphys, and none with bicornuate uterus. Mean intercervical distance was significantly greater (P < .001) in uterus didelphys (12.05 mm) compared with septate (5.43 mm) or bicornuate uterus (5.40 mm).

Septate uterus is as common as uterus didelphys, and considerably more common than bicornuate uterus, in women with a double cervix. Although a widened intercervical distance may support the MRI diagnosis of uterus didelphys, careful evaluation of the uterine fundus is required for correct diagnosis when encountering a double cervix.