Congenital abnormalities of the uterus, or congenital müllerian anomalies, include a spectrum of uterine abnormalities caused by abnormal embryologic fusion and canalization of the müllerian ducts to form a normal uterine cavity. These anomalies are often asymptomatic and unrecognized, but have a reported prevalence of approximately 2-4% in reproductive age women, and up to 5-25% in women with adverse reproductive outcomes. However, the true incidence is unknown as screening for uterine anomalies is typically only performed in women with certain adverse pregnancy outcomes or abnormal gynecologic symptoms.
The presence of a uterine anomaly appears to increase the risk of adverse pregnancy outcomes such as preterm birth, fetal growth restriction, malpresentation, cesarean delivery, and preeclampsia. A uterine septum also appears to increase the risk of early pregnancy loss. There is an association between uterine anomalies and renal (kidney) anomalies as they have related embryologic precursors.
Classification of uterine anomalies usually follows the 1988 American Fertility Society classification and includes: hypoplasia/agenesis, unicornuate, didelphys, bicornuate, septate, arcuate, and DES drug related. In some instances, uterine anomalies fall between two categories and are classified as hybrid or complex. Nonsurgical diagnosis of uterine anomalies can be made by ultrasound, MRI, or hysterosalpingogram. Saline-infusion-sonohysterogram (SIS) is a highly reliable diagnostic study with over 95% accuracy.
Women with uterine abnormalities should be followed closely in pregnancy due to the increased risk of complications. Also, they should have a kidney ultrasound to ensure they have two normal appearing kidneys.
Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!