Müllerian duct anomalies (MDAs) are congenital abnormalities that occur when the Müllerian ducts (paramesonephric ducts) do not develop correctly. This may be due to complete agenesis, defective vertical or lateral fusion, or resorption failure.

Epidemiology

MDAs are estimated to occur in 1-5% of all women. There is a higher rate of women with repeated miscarriages (3-15%) ^2,5. 

Associations

Renal anomalies are frequently associated, most commonly renal agenesis but also crossed fused renal ectopia, and duplex kidney ². 

Müllerian anomalies are associated with higher rates of endometriosis, particularly in obstructive cases. Surgical removal of uterine remnants or blockages has been shown to alleviate symptoms of endometriosis ⁶.

Clinical presentation

Despite these anomalies being common ¹, the majority are asymptomatic. Obstruction of the Müllerian duct may occur, and patients present with an abdominal mass and dysmenorrhea. Delayed treatment may result in severe consequences and potentially infertility. Patients may also present with recurrent miscarriages and infertility ^2,5. 

Pathology

Subtypes

• uterine agenesis: ~10%

• arcuate uterus: often considered as part of normal anatomical variation, ~7%

• unicornuate uterus: ~15% (range 5-25%)

• uterine duplication anomalies

  • uterus didelphys: ~7.5 % (range 5-11%)

  • bicornuate uterus: ~25% (range 10-39%)

  • septate uterus: ~45% (range 34-55%)

    • subseptate uterus

Classification

Various classification systems have been proposed without a clear consensus as which to use ⁵. The more commonly used systems include:

• AFS classification of Müllerian anomalies ⁷

• ASRM Müllerian anomalies classification 2021 ⁸

• ESHRE/ESGE consensus on diagnosis of female genital anomalies ⁹

Radiographic features 

Ultrasound

• should be performed initially

• confirms any structural abnormalities of the genital tract

• sometimes cannot help to identify the type of MDA (especially on 2D imaging alone)

• 3D coronal transvaginal imaging has a high degree of diagnostic accuracy and ideally should be performed in the secretory phase of the menstrual cycle

MRI

• valuable non-invasive technique

• evaluation of the female pelvic anatomy

• accurate Müllerian duct anomaly classification

Treatment and prognosis

Many patients are asymptomatic and require no treatment. However, where obstruction occurs, surgical intervention is usually required and may result in permanent infertility - counseling is required.

See also

• Müllerian duct

• uterus