# Müllerian Uterine Anomalies > Müllerian uterine anomalies in NEET-PG Obstetrics and Gynaecology: ASRM classes, diagnosis, septate uterus and surgery. - Canonical URL: https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/uterine-anomalies - Exam / course: NEET-PG · Subject: Obstetrics and Gynaecology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Müllerian Uterine Anomalies", PrepElephant, https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/uterine-anomalies ## Direct answer Müllerian anomalies arise when the two paramesonephric ducts fail to develop, fuse or resorb their central septum, producing a spectrum from unicornuate to septate uteri that affects roughly 5 to 7 per cent of women overall — and several-fold more of those with recurrent pregnancy loss. The ASRM classification (updated 2021, paralleled by ESHRE/ESGE) orders them by developmental step: hypoplastic/unicornuate (formation defects), didelphys and bicornuate (fusion defects), septate and arcuate (resorption defects). Clinically the septate uterus is the one to know cold — the commonest anomaly in recurrent pregnancy loss, treated effectively by hysteroscopic septoplasty — while a didelphys with an obstructed hemivagina and absent kidney (Herlyn-Werner-Wunderlich triad) is the classic adolescent presentation with dysmenorrhoea and a pelvic mass. Three-dimensional ultrasound or MRI defines the external uterine contour, the single distinction separating a septate (normal fundal contour) from a bicornuate (heart-shaped fundus) uterus — and therefore deciding whether the treatment is a hysteroscope or nothing. ## What you must remember - **Prevalence by population:** about 5-7 per cent of unselected women, rising substantially with recurrent first-trimester loss and higher still with second-trimester loss — recurrent pregnancy loss is the complaint that should trigger a search. - **ASRM classes:** I hypoplasia/agenesis (MRKH syndrome — absent uterus and upper vagina, normal ovaries, 46,XX); II unicornuate, often with a rudimentary horn; III didelphys; IV bicornuate; V septate; VI arcuate; VII diethylstilboestrol-related (T-shaped), historical but still examined. - **Which anomaly does what:** septate — miscarriage and preterm labour (worst obstetric record, best treatment); bicornuate and didelphys — preterm birth, malpresentation, no role for unification surgery today; unicornuate — infertility, rudimentary horn pregnancy, renal agenesis on the absent side. - **The renal association:** unilateral renal agenesis or ectopia accompanies unicornuate and didelphys anomalies, so renal ultrasound is part of the workup — an exam favourite. - **Diagnosis:** 3D ultrasound and MRI are the contour-defining tests; combined hysteroscopy-laparoscopy was the classical gold standard; HSG shows the cavity but not the serosal surface and cannot alone separate septate from bicornuate. - **Treatment logic:** hysteroscopic septoplasty for septate and deep arcuate uteri; excision of a non-communicating rudimentary horn; obstructed hemivagina drained at diagnosis; cerclage individualised; no surgery for asymptomatic didelphys or bicornuate. - **Obstetric plan:** growth surveillance, anticipation of malpresentation and delivery planning — but most women with fusion defects deliver viable infants. ## How the diagnostic pathway runs A 26-year-old with three consecutive first-trimester miscarriages has a normal hormonal and karyotype workup. HSG shows a "broad, partially split cavity". The pivotal next step is not surgery but 3D ultrasound or MRI: if the fundal serosa is convex or flat, the uterus is septate and hysteroscopic septoplasty is offered, after which miscarriage rates fall dramatically in most series; if the fundus shows an external cleft deeper than about 1 cm, it is bicornuate, metroplasty has no modern role, and she is managed with cervical length surveillance in the next pregnancy. A renal ultrasound looks for accompanying agenesis. Contrast the adolescent attending the emergency department with worsening monthly dysmenorrhoea despite regular menses and a paravaginal mass: didelphys with obstructed hemivagina (with ipsilateral renal agenesis completing the Herlyn-Werner-Wunderlich triad) is the diagnosis, confirmed on MRI and drained surgically. Both cases reduce to the same principle: define the developmental step that failed, define the external contour, and let that decide the instrument. ## Where students slip Three confusions dominate. First, septate versus bicornuate — students call every "double cavity" a bicornuate uterus and offer metroplasty; the exam expects the contour rule (external fundal cleft means bicornuate, normal external fundus with internal septum means septate) and hysteroscopic treatment for the septum only. Second, MRKH versus androgen insensitivity: both present with primary amenorrhoea and absent uterus, but MRKH is 46,XX with normal female external genitalia, while complete androgen insensitivity is 46,XY with testes and absent or sparse pubic hair — a lifelong viva favourite. Third, forgetting that unicornuate and didelphys carry renal anomalies, so an "absent kidney" on a young woman's scan should prompt uterine evaluation too. ## Frequently asked questions ### Which Müllerian anomaly is most associated with recurrent pregnancy loss? The septate uterus, because the fibrous septum has poor blood supply; it is also the most correctable, by hysteroscopic septoplasty. ### How do you distinguish septate from bicornuate uterus on imaging? By the external fundal contour: a septate uterus has a normal external fundus with an internal septum, while a bicornuate uterus shows an external fundal cleft — best seen on 3D ultrasound or MRI. ### What is the Herlyn-Werner-Wunderlich syndrome? Uterus didelphys with an obstructed hemivagina and ipsilateral renal agenesis, presenting in adolescence with dysmenorrhoea and a pelvic mass despite regular periods. ### Which anomaly accompanies MRKH syndrome and what is the karyotype? Mayer-Rokitansky-Küster-Hauser syndrome is class I hypoplasia/agenesis of the uterus and upper vagina in a 46,XX woman with normal ovaries and secondary sexual characteristics. ### Do all Müllerian anomalies require surgical correction? No — didelphys, bicornuate and arcuate uteri are managed expectantly with obstetric surveillance; surgery is reserved for septate uterus, non-communicating rudimentary horns and obstructed variants.