Mullerian Abmormalities Flashcards
Mullerian ducts are also known as
Paramesonephric ducts
Development of the female reproductive tract depends on what major hormones?
The ABSENCE of AMH -> mullerian ducts persist and develop.
Lack of testosterone -> Wolffian ducts regress.
Oestrogen -> promotes differentiation od the uterus, fallopian tubes and vagina.
Describe the 3 main stages of normal mullerian tract development
- Formation (weeks 5-6)
- Fusion (weeks 8-12)
- Canalization and differentiation (weeks 12-20)
Formation the mullerian ducts
Weeks 5-6
Arise from the coelemic epithelium on the lateral sides of the urogenital Ridge
Develop alongside the Wolffian (mesonephric) ducts which will later regress in females.
(This stage occurs in both male and female embryos)
Fusion of the mullerian ducts
Weeks 8-12
Fuse in the middle to form a single, central uterovaginal canal.
The unfused upper parts remain as the fallopian tubes.
Canalization and differentiation
12-20 weeks
Fused portion of the mullerian ducts undergo canalization to form the:
- uterus (fused mid portion)
- cx (lower fused portion)
- upper 1/3 of the vagina (caudal fused end)
Unfused upper portion = fallopian tubes.
The urogenital sinus contributes to the formation of the lower 1/3 of the vagina
Mullerian genesis
Failure of mullerian duct development leads to absent uterus and upper vagina (but normal ovaries and secondary sexual characteristics)
Uterine abnormalities (e.g. separate or bicornuate uterus)
Incomplete fusion or resorption defects of mullerian ducts
Uterine abnormalities (separate or bicornuate uterus)
Incomplete fusion or resorption defects of mullerian ducts
Persistent mullerian ducts syndrome
AMH deficiency or receptor mutation causes mullerian structures (uterus, fallopian tubes) to persist in males
Class 1: hyperplasia or agenesis
MRKH (Mayer-Rokitansky-Kuster-Hauser) syndrome.
Complete or partial agenesis of the uterus and upper vagina.
Normal ovarian function (because ovaries derived from the gonadal ridge, not mullerian structures).
Common presentation: primary amenorrhoea with normal secondary sexual chx
Class II: unilateral hyperplasia
Unicornuate uterus.
Failure of one mullerian duct to fully develop.
Often associated with a non- communicating horn, which may have functional endometrium (leading to hematometra and cyclical pain)
Class III-IV: defective fusion
Uterine didelphus (III) - complete failure of fusion, resulting in two uterine and two endometrial cavities. Often with an associated longitudinal vaginal septum.
Bicornuate uterus (IV) - Partial failure of fusion, resulting in two endometrial cavities, sharing a single external contour.
Class V: incomplete resorption
Septate uterus - failure of midline septum resorption leads to a persistent fibrous or muscular septum dividing the endometrial cavity.
MOST COMMON mullerian anomaly and strongly associated with recurrent pregnancy loss.
Differentiation from bicornuate uterus requires MRI or 3D USS.
Class VI: arcuate uterus
A mild midline indentation of the fundus due to incomplete resorption.
Considered normal variant with minimal clinical significance.
Class VIII - Diethylstilbestrol (DES) - Related Anomaly
In utero DES exposure leads to a hypoplastic, T-shaped endometrial cavities with increased miscarriage risk
Unicornuate uterus pregnancy implications
High risk of miscarriage (50%), IUGR, and second trimester loss, PTB rate = 40%. Rudimentary horn (if function) can cause ectopic pregnancy
Uterine didelphys
Increased miscarriage risk, but better pregnancy outcomes than bicornuate uterus. Can have normal pregnancy if one cavity is well developed. Miscarriage rate 40% PTB rate 20%
Bicornuate uterus
High risk second trimester loss, PTB, malpresentation, and associated with FGR. Miscarriage rate 40%, PTB rate 30-40%
Septate uterus
Highest miscarriage rate among mullerian anomalies. Commonly associated with recurrent pregnancy loss. Surgical correction (metroplasty) improves outcomes significantly. Miscarriage rate 60%, PTB rate 20%.
Arcuate uterus
Generally considered a normal variant with minimal impact on pregnancy. Miscarriage rate slightly increased- 10-20%, minimal increase in PTB.
DES related anomaly
High rush of miscarriage, PTB, ectopic pregnancy, cervical incompetence due to a hypoplastic endometrium. Miscarriage rate 50%, PTB 30%.
