Undiagnosed uterine anomalies revealed by breech on ultrasound prior to external cephalic version - A chance to take a closer look.

OBJECTIVE

Uterine anomalies (UA) occur in up to 6.7% of women. Breech is eight times more likely to occur with UA which may not be diagnosed prior to pregnancy and may only be found in the third trimester with breech. The objective of the study is to assess the prevalence of both already known and newly sonographically diagnosed UA in breech from 36 weeks of gestation and its impact on external cephalic version (ECV), delivery options and perinatal outcomes.

STUDY DESIGN

We recruited 469 women with breech at 36 weeks of gestation over a 2-year period at the Charité University Hospital, Berlin. Ultrasound examination was performed to rule out UA. Patients with known and newly 'de novo' diagnosed anomalies were identified and delivery options and perinatal outcomes analyzed.

RESULTS

The 'de novo' diagnosis of UA at 36-37 weeks of pregnancy with breech was found to be significantly higher compared to the diagnosis prior to pregnancy with 4.5% vs 1.5% (p < 0.001 and odds ratio 4 with 95% confidence interval 2.12-7.69). Anomalies found included 53.6% bicornis unicollis, 39.3% subseptus, 3.6% unicornis and 3.6% didelphys. A trial of vaginal breech delivery was successful in 55.5% of cases when attempted. There were no successful ECVs.

CONCLUSION

Breech is a marker for uterine malformation. Diagnosis of UA with breech can be up to four times improved with focused ultrasound screening in pregnancy even from 36 weeks of gestation prior to ECV to identify missed anomalies. Timely diagnosis aids antenatal care and delivery planning. Importantly, definitive diagnosis and treatment can be planned postpartum to improve outcomes in future pregnancies. ECV plays a limited role in selected cases.