Unicornuate

Unicornuate refers to a congenital uterine anomaly in which only one of the paired Müllerian ducts develops, resulting in a single uterine horn. In this condition the uterus is typically single-homed and may have a normal outer contour, but the opposite side is underdeveloped or absent. A contralateral rudimentary horn can be present, and such a horn may be non-communicating or have a small cavity that communicates with the main uterine cavity in some cases.

The unicornuate uterus is one of several Müllerian duct anomalies and is often discussed in relation to a rudimentary horn. The rudimentary horn, when present, can contain functional endometrium, which may lead to hematometra or endometriosis-like symptoms. The condition is frequently associated with renal system anomalies, especially unilateral renal agenesis, due to shared embryologic development.

Clinical presentation varies. Many individuals are asymptomatic and discover the anomaly incidentally. Others may experience dysmenorrhea, pelvic pain, or infertility. Pregnancy is possible but carries increased risks, including miscarriage, growth restriction, abnormal fetal presentation, preterm birth, and, in some cases, uterine rupture if pregnancy occurs in a non-communicating rudimentary horn. Diagnosis is with imaging, typically transvaginal ultrasound, advanced ultrasound techniques such as 3D ultrasound, magnetic resonance imaging, and sometimes hysterosalpingography. Laparoscopy and hysteroscopy can provide definitive assessment.

Management depends on symptoms and associated anomalies. Asymptomatic cases may require observation. If a rudimentary horn has functioning endometrium or there are recurrent complications, surgical excision of the rudimentary horn is often indicated. Obstetric management for pregnancies in a unicornuate uterus is generally high risk, with careful monitoring and planning for potential complications.