Uterine congenital anomalies are a collection of dysmorphisms attributable to failure of Müllerian duct development. The Müllerian or Paramesonephric ducts are paired embryological structures that run down the sides of the urogenital ridge which in females become the Uterus and upper one third of the vagina.
7%8% of women are thought to have a structural anomaly of the uterus. Whereas >25% of women with recurrent spontaneous abortions may have anomalies. Some of these anomalies are not very detrimental to female reproduction, while others are very much so.
The normal adult uterus measures approximately
7.5 cm in length, 5 cm in width and 2.5 cm thick.
It is approximately 30-40 grams in weight and divided into fundus, body and cervix.
The Müllerian anomalies are categorized into 7 classes with subgroups.
Class I: Müllerian agenesis or hypoplasia
(Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome)
Varying degrees of vaginal and uterine agenesis with a prevalence of 1 in 5000 newborn females.
Class II: Unicornuate uterus
Agenesis or hypoplasia of one of the two Müllerian ducts may have a communicating or non-communicating rudimentary horn.
prevalence 2.4-13% of all müllerian anomalies
Class III: Didelphys
Failure of fusion of the Müllerian ducts along the whole uterine length 2 uterine bodies and 2 cervices
prevalence 11% of uterine malformations
Class IV: Bicornuate uterus
Incomplete fusion of the uterine horns at the level of the fundus
60% of patients can expect to deliver a viable infant
Class V: Septate uterus
Absent or incomplete resorption of the uterovaginal septum.
incidence of both complete and partial uterine septi is 33.6%
Class VI: Arcuate uterus
A mild indentation at the level of the fundus from a near-complete resorption of the uterovaginal septum.
Class VII: Diethylstilbestrol (DES) T-shaped uterus
resulting from DES exposure of the patient in utero (less common since its withdrawal).
Knowing the varieties of uterine anomalies is of importance for the sonographer as these conditions can come with increased risk of pregnancy failures and other gynecological conditions.
Henry Suarez RDMS, RVT
Acien P. Reproductive performance of women with uterine malformations. Hum Reprod 1993;8:122.