Congenital anomalies of the uterus
Congenital anomalies of the uterus (Mullerian duct anomalies) do not seem to directly correlate with subfertility issues, except for uterus aplasia and its variations, as well as cervical and vaginal atresia and the complete transverse vaginal septums.
Laparoscopy aids in diagnosis, confirmation and classification of most of the congenital anomalies of the uterus, in combination with hysterosalpingography and hysteroscopy. Especially useful is the differential diagnosis between the didelphys and the septate uterus (with two cavities) with single or double cervical canal.
In septate uterus, the uterus appears normal on the outer in size and shape, while in didelphys uterus there are two uterine horns that join together at their lower part. Diagnosis is of great importance since in septate uterus, the section of the septum is performed with hysteroscopic surgery techniques, while in didelphys uterus the reconstructive surgery Strassmann- Jones procedures that are undertaken with laparotomy may be applied.
In order to comprehend the congenital anomalies of the uterus it is necessary to refer to elements of embryology of the female genital tract.
The fallopian tubes, the uterus (body and cervix) and the upper two thirds of the vagina are formed during embryonic life from the peremesonephric ducts (also known as Mullerian ducts). Defects in the formation of an organ during pregnancy (congenital anomalies) may be due to an inherent defect or the action of an external harmful factor. Harmful factors that may result in congenital anomalies in all the systems of an embryo include infections, toxic substances, environmental causes etc.
It must be noted that the development of the gonads is separate of that of the Mullerian ducts, which means that in cases of congenital absence or anomalies of the vagina-uterus-fallopian tubes the ovaries are normal and functional. Mullerian duct anomalies are not accompanied by sex-chromosome anomalies.
After the development and fusion of the Mullerian ducts, the septum between them fuses and the anomalies that may arise are distinguished in:
- development anomalies,
- fusion anomalies that may be lateral or vertical.
Development anomalies include the absence of both Mullerian ducts, the absence of one Mullerian duct, the incomplete development in both Mullerian ducts and the incomplete development of one Mullerian duct.
Complete failure of development of the Mullerian ducts is manifested with the absence of uterus. Incomplete development of both Mullerian ducts may result in hypoplasia or absence of the uterus, absence of the remainder or part of the tubes and absent, rudimentary or imperforate vagina. Incomplete development of one Mullerian duct may result in unicornuate uterus with a hypoplastic horn etc.
Lateral fusion anomalies may result in:
- arcuate uterus,
- septate or subseptate uterus,
- bicornuate uterus,
- didelphys uterus,
- septate or subseptate vagina.
Vertical fusion anomalies may result in:
- cervical atresia,
- vaginal atresia,
- transverse vaginal septum.