Müllerian anomalies

Lore & Background

Müllerian duct anomalies arise from defects in three phases of embryogenesis. Class I and II anomalies result from underdevelopment of primitive uterine and vaginal pockets due to an arrest in stage one. Class III and IV anomalies stem from failure of midline fusion in stage two, while class V and VI anomalies occur from failure of midline degeneration in stage three. Class VII anomalies are caused by diethylstilbestrol (DES).

Mayer–Rokitansky–Kuster–Hauser (MRKH) syndrome, a class I anomaly, involves underdeveloped or absent vagina and uterus in females with normal 46,XX karyotype and functioning ovaries. Genetic causes include mutations in WNT4, HNF1B, and LHX1, as well as copy number variants such as deletion of 17q12. Clinical presentations vary from asymptomatic before puberty to pelvic pain, abnormal bleeding, or amenorrhea.

Diagnosis relies on ultrasound and MRI, which can differentiate septate uterus from bicornuate uterus. Non-surgical treatment includes the Frank and Ingram procedure using graduated dilators. Surgical options include the McIndoe procedure (skin graft) and sigmoid vaginaplasty (using a segment of sigmoid colon), each with specific complications.

Reader's Guide

Müllerian duct anomalies are significant because they represent a common cause of infertility, recurrent pregnancy loss, and obstetric complications in affected women. The ASRM classification system provides a standardized framework for diagnosis and treatment planning, distinguishing seven anatomical classes that guide clinical management. MRKH syndrome, the most recognized class I anomaly, highlights the interplay between genetic and developmental factors, with identified mutations in WNT, HNF1b, and LHX1 genes, as well as 17q12 deletions. These anomalies often co-occur with extragenital defects, such as urological and skeletal malformations, underscoring the broader developmental impact. Treatment options range from non-surgical dilation to surgical reconstruction, each with distinct success rates and risks. The legacy of DES as a cause of class VII anomalies serves as a historical caution about environmental influences on fetal development. Understanding these anomalies continues to improve reproductive outcomes through early diagnosis and tailored interventions.

Did You Know?

• Müllerian duct anomalies affect between 4% and nearly 7% of the female population.
• Class I anomalies include Mayer–Rokitansky–Kuster–Hauser (MRKH) syndrome, where the vagina and uterus are underdeveloped or absent.
• A commonly identified genetic cause is a deletion of 17q12, resulting in loss of the HNF1B and LHX1 genes.
• The Frank and Ingram procedure uses graduated dilators to create a functional vagina over months to years.