Four cardinal steps in Mullerian development
- Elongation → Mullerian ducts start as buds and then elongate
- Fusion → solid tubes fuse and remain solid. They are not hollow.
- Septal Resorption
Obstructive vs. Non-obstructive defects
- “Obstructive” lesions = completely or partially block obstruction of menstrual outflow and / or prevent or impede vaginal intercourse.
- Obstructive lesions include transverse vaginal septum, described in detail below.
- “Non-obstructive” lesions include everything else, including a bicornuate uterus
Example of failure of elongation of ducts (bilateral)
- condition: mullerian agenesis
Example of failure of elongation of ducts (unilateral)
- condition: Unicornuate Uterus
Example of failure of fusion of ducts
- condition: uterine didelphys
Example of failure of canalization
- condition: vaginal agenesis
Example of failure of septal resorption
- condition: septate uterus
Unicornate uterus: congential origins, symptoms
- Congenital origins: the uterus is formed from one only of the paired Müllerian ducts while the other Müllerian duct does not develop or only develops in a rudimentary fashion
- Symptoms: Women with the condition may be asymptomatic and unaware of having a uniconuate uterus; normal pregnancy may occur.
Unicornate uterus: treatment, reproductive consequences
Treatment: Remove obstructing abnormalities
Reproductive Consequences: Patients with a unicornuate uterus are at a higher risk for pregnancy loss and obstetrical complications. Once the small horn can no longer accommodate growth, it will rupture, causing significant hemorrhage.
Mullerian agenesis: congenital origins, sx
- Congenital origins: failure of the müllerian ducts to develop, resulting in a missing uterus and fallopian tubes and variable malformations of the upper portion of the vagina.
- Symptoms: Primary amenorrhea
Mullerian agenesis: tx, reproductive consequences
Treatment: there are treatments to increase the comfort in sexual intercourse, there are none to let the woman herself become pregnant.
Reproductive consequences: If there is no uterus, women with MRKH cannot carry a pregnancy. However, it is possible for these women to have genetic offspring by in vitro fertilisation (IVF) and surrogacy in someone else.
Didelphys: congenital origins
- the fusion of the two paramesonephric ducts (also called mullerian ducts) ==> uterus
- This process usually fuses the two mullerian ducts into a single uterine body but fails to take place in these affected women who maintain their double mullerian systems.
- A didelphic uterus will have a double cervix and is usually associated with a double vagina.
Didelphys: sx, reproductive consequences
Symptoms: may be asymptomatic and unaware of having a double uterus. Gynecological complaints include dysmenorrhea and dyspareunia.
May need special attention during pregnancy as premature birth and malpresentation are common
In some studies has also been found associated with higher rate of infertility, spontaneous abortion
Vaginal atresia: congenital origins
- Congenital origins: urogenital sinus fails to contribute the caudal portion of the vagina.
- The lower fifth to third of the vagina is replaced by 2 to 3 cm of fibrous tissue, above which lie a well-differentiated upper vagina, cervix, uterine corpus, and fallopian tubes
Vaginal atresia: sx, tx, reproductive consequences
Symptoms: Hydrometrocolpos (watery fluid in uterus and vagina), primary amennorhea
Treatment: Reconstructive surgery
Reproductive consequences: unknown to us
Transverse vaginal septum: congenital origins
- Canalization of the mullerian tubercle and sinovaginal bulb is necessary to give a normal vaginal lumen.
- If the area of junction between these structures is not completely canalized, a transverse vaginal septum will occur.
- This may be partial or complete and generally lies at the junction of the upper third and lower two thirds of the vagina.
Transverse vaginal septum: sx
- prepubertal state, diagnosis is generally not made unless there is the development of a mucocolpos or mucometrium behind the septum.
- In these girls an unexplained abdominal mass forms.
- At puberty, however, if the septum is complete, hematocolpos and hematometrium may occur
- pt complains of primary amenorrhea with cyclic cramping.
- incomplete may have some bleed, but also ==> hematocolpos/hematometrium
Transverse vaginal septum: tx
- If the septum is incomplete or thin, it can be expanded by manual dilation or simple incision, with suturing of the edges of the vagina on either side.
- In cases of a thick septum, the two areas of the vagina may be quite distant.
- In such cases excision may require the implantation of a split-thickness skin graft in a fashion similar to the Abee-McIndoe procedure.
Septate uterus: congenital origins
- During this fusion of uterus a resorption process eliminates the partition between the two ducts to create a single cavity.
- This process begins caudally and advances cranially, thus a complete septum formation represents an earlier disturbance of this absorption than the incomplete form.
Septate uterus: sx, tx, reproductive consequences
Symptoms: may not be known to the affected individual and not result in any reproductive problems; thus normal pregnancies may occur.
Reproductive Consequences: High rate of first trimester pregnancy loss due to poor vascularity of septum, premature birth, and malpresentation.
Treatment: Septum can be resected with surgery.
Diethylstilbestrol (DES) congenital defects as result of mother’s use during pregnancy: gyn defects
- a T-shaped uterus
- small hypoplastic uterus
- constriction bands
- widened lower uterine segment
- narrow fundal segment of endometrium
- irregular endometrial margins
- intraluminal filling defects.
Diethylstilbestrol (DES) congenital defects as result of mother’s use during pregnancy: sx, tx
Reproductive consequences: two-fold increase in spontaneous abortion, nine-fold increase in ectopic gestation. Also an association with premature labor and perinatal mortality. Also increased risk of vaginal clear cell carcinoma.
Male babies: cryptorchidism, hypospadias, and infertility.
Key point: monitor for clear cell vaginal cancer, ectopic pregnancy, cervical incompetence