Anomalies of the Female Genital Tract

Anomalies of the female genital tract are congenital structural abnormalities from abnormal development, fusion, or canalisation of the paramesonephric (Müllerian) ducts. The spectrum runs from complete Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome) through patterns of uterine and vaginal duplication and septation, to obstructive anomalies (including imperforate hymen and transverse vaginal septum).

Presentation varies with the anomaly:

• Primary amenorrhoea with normal secondary sexual characteristics, raising suspicion of Müllerian agenesis or an obstructive anomaly.
• Recurrent pregnancy loss or preterm birth in a woman with an unrecognised uterine anomaly, identified only during reproductive investigation.
• Cyclical pelvic pain from an obstructed, functioning uterine or vaginal remnant.

Careful, structured clinical and imaging assessment is needed to characterise the anomaly and guide individualised management.

Classification and pathophysiology

• Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome) is failure of normal paramesonephric duct development, with absence or significant hypoplasia of the uterus and upper vagina. Ovarian function and external genitalia are normal, because the ovaries have a distinct embryological origin separate from the Müllerian duct derived structures. Affected individuals develop normal secondary sexual characteristics at puberty but present with primary amenorrhoea because the uterus is absent or rudimentary. It is the second commonest cause of primary amenorrhoea overall.
• Uterine anomalies from abnormal fusion of the paired paramesonephric ducts:
  • Uterine didelphys: complete failure of fusion, giving two separate uterine cavities, cervices, and frequently a longitudinal vaginal septum.
  • Bicornuate uterus: partial fusion failure, giving two uterine horns sharing a single cervix.
  • Septate uterus: normal external fusion but incomplete resorption of the intervening septum, giving a single external contour but a divided internal cavity.
• Septate uterus carries the highest recognised risk of adverse reproductive outcome (recurrent miscarriage and preterm birth) among the fusion anomalies. This is believed to reflect the poor vascularity and decidualisation capacity of the fibrous, avascular septal tissue.
• Imperforate hymen is complete absence of a hymenal opening, a failure of canalisation at the most distal, vaginal introital level.
• Transverse vaginal septum is a failure of canalisation at a more proximal level within the vaginal canal. It reflects abnormal fusion between the Müllerian duct derived upper vagina and the urogenital sinus derived lower vagina.
• Both obstruct outflow of menstrual blood once menarche occurs. The presentation is cyclical pelvic pain with primary amenorrhoea, from accumulation of obstructed menstrual blood within the uterus and, depending on the level of obstruction, vagina (haematometrocolpos).

• Müllerian agenesis presents with primary amenorrhoea in an adolescent with otherwise normal pubertal development and secondary sexual characteristics. Examination shows a shortened or absent vagina. This pattern distinguishes it from other causes of primary amenorrhoea.
• Müllerian agenesis is associated with renal and, less commonly, skeletal anomalies, given the shared embryological timing and proximity of these structures. Screen proactively for these once the diagnosis is confirmed or strongly suspected.
• Imperforate hymen and transverse vaginal septum present with cyclical, often severe pelvic or lower abdominal pain in a pubertal girl with primary amenorrhoea, reflecting cyclical accumulation of obstructed menstrual blood.
• Imperforate hymen shows a visible, bulging, often bluish-tinged membrane at the vaginal introitus, from accumulated blood seen through the thin hymenal membrane.
• A more proximal transverse vaginal septum may not be visible on external examination alone and needs imaging for characterisation.
• Uterine fusion anomalies frequently remain asymptomatic and undetected until found incidentally on imaging for another indication. More commonly they are identified during investigation of recurrent pregnancy loss, preterm birth, or fetal malpresentation. Clinical significance and reproductive risk vary considerably with the anomaly.
• Renal anomalies coexist with a substantial proportion of Müllerian anomalies, reflecting their closely related embryological timing. This is particularly well established for uterine didelphys and Müllerian agenesis. Renal imaging is an essential component of assessment in any confirmed or strongly suspected Müllerian anomaly.

• Pelvic ultrasound is the standard, first line imaging investigation for suspected Müllerian anomaly. It gives initial characterisation of uterine and, where relevant, vaginal anatomy.
• Magnetic resonance imaging gives superior anatomical detail and is generally recommended for definitive diagnosis and accurate classification. Classification directly affects management and reproductive counselling.
• Three-dimensional ultrasound, where available, improves anatomical characterisation over standard two-dimensional ultrasound. It is particularly valuable for distinguishing between uterine fusion anomaly subtypes, which can be challenging to differentiate on standard imaging alone.
• Examination under anaesthesia, with diagnostic laparoscopy and hysteroscopy in selected cases, may be needed for complex anomalies or where imaging alone is insufficient. This is particularly relevant where surgical correction is planned and precise anatomy is essential to choosing the surgical approach.
• Renal tract imaging (ultrasound as the standard initial approach) is an essential component of evaluation of any confirmed or strongly suspected Müllerian anomaly, given the well established association between these two organ systems, reflecting their shared embryological origin and timing.
• Karyotype and hormonal evaluation (including gonadotropin and testosterone levels) may be appropriate in primary amenorrhoea to distinguish Müllerian agenesis from other diagnoses in its differential.
• This is particularly relevant to excluding androgen insensitivity syndrome, which can present with a superficially similar picture of primary amenorrhoea with absent or rudimentary uterine structures.

• Imperforate hymen and transverse vaginal septum causing symptomatic obstruction require surgical correction, by an experienced specialist gynaecological surgical team.
• Imperforate hymen is managed by a relatively straightforward hymenotomy (surgical incision and drainage of the obstructed menstrual blood).
• Transverse vaginal septum is typically more proximal and complex. It generally requires more extensive surgical resection and vaginal reconstruction.
• Müllerian agenesis management focuses on creating a functional vagina to support future sexual function.
• Progressive vaginal dilator therapy is the generally preferred, first line approach because it is less invasive. It uses specifically designed dilators for gradual dilation over a structured treatment period.
• Surgical vaginoplasty is used where dilator therapy is inadequate or not appropriate.
• Defer intervention until the individual is developmentally and psychologically ready to engage with and adhere to treatment.
• Offer full psychological support, given the substantial emotional impact of the diagnosis, particularly its implications for fertility (the uterus is absent). Future biological parenthood requires surrogacy using the individual's own oocytes, as ovarian function is normal and preserved.
• Uterine fusion anomalies are generally managed conservatively in the absence of adverse reproductive history. Many affected women have a favourable reproductive outcome despite the anomaly.
• Consider surgical correction for recurrent pregnancy loss attributed to the identified anomaly, after counselling on benefits and risks. Hysteroscopic septum resection for septate uterus has well established evidence of improved reproductive outcome and is relatively minimally invasive.
• Individualised reproductive counselling covers the implications of the anomaly for fertility, pregnancy, and delivery. Certain anomalies, including uterine didelphys and bicornuate uterus, carry an increased risk of fetal malpresentation and preterm birth. They warrant proactive obstetric surveillance and management planning in any subsequent pregnancy.
• Psychological support addresses the potentially substantial emotional impact of a diagnosis affecting fundamental aspects of reproductive and sexual identity and function. Connect patients to support resources and, where appropriate, peer support networks.
• Care is ideally delivered through a specialist multidisciplinary paediatric and adolescent gynaecology service with expertise in this relatively uncommon area of practice.