Incomplete fusion of the Mullerian or paramesonephric ducts results in the most common types of uterine malformation:
Complete failure results in uterus didelphys. This extremely rare condition is characterised by:
- double vagina
- double cervix
- entirely double uterus ie. two single-horned uteruses
A variant of this is the uterus bicornis bicollis which is characterised by:
- double or single vagina
- double cervix
- two single-horned uteruses which show partial fusing of their muscular walls
More extensive fusion of the Mullerian ducts results in the uterus bicornis unicollis which is characterised by:
- single vagina
- single cervix
- double, single-horned uteruses which are partially fused
Other abnormalities include:
- uterus subseptae - uterus has midline septum
- uterus arcuatus - uterus slightly indented in the middle
- uterus unicornis - with a second blind-ending rudimentary horn
A septate vagina or a double vagina may occur in isolation if canalisation of the most caudal part of the fused Mullerian duct is incomplete.
NICE give a broader definition of a septate uterus
- a septate uterus is a type of congenital uterine anomaly, in which the inside of the uterus is divided by a muscular or fibrous wall, called the septum
- septum may be partial or complete, extending as far as the cervix. It is more common in women with infertility and in women with repeated miscarriage and may therefore be one cause of this problem
- surgical removal of the septum (metroplasty) is usually considered for women who have a septate uterus and repeated adverse reproductive outcomes, including miscarriage and preterm delivery
- surgery was traditionally done by a transabdominal approach but recently a hysteroscopic approach has been proposed, to reduce morbidity and shorten the recovery period. In addition, unlike transabdominal metroplasty, caesarean section is not mandatory for patients who conceive after hysteroscopic metroplasty
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