Müllerian (Uterine) Abnormalities and Infertility

Minimally invasive surgical procedures may help women with uterine abnormalities get pregnant

A relatively common cause of infertility and poor pregnancy outcome, the so-called Müllerian anomalies, are often treatable surgically. These abnormalities are congenital, which means that a woman is born with the abnormality.

Since these abnormalities don’t often have any symptoms unless the woman is trying to conceive, they are often a surprise diagnosis. They are detected only with the evaluation that takes place when a woman is either infertile, or has suffered from multiple miscarriages.

Occasionally, the abnormalities are “obstructive,” which means that menstrual flow is blocked. Having nowhere to go, the accumulated blood and other menstrual products can cause severe pain. In these cases, the young woman will come to clinical attention near the time in puberty when she starts having menstruation.

In order for the uterus and upper vagina to develop normally during female development, two tubal structures first elongate alongside each other. These dense tubes then “canalize” or develop a lumen. The two tubes then unify into one structure with a residual septum or wall between the two sides. The final step is the elimination of the septum. Failure of any of these steps will result in a uterine abnormality.

For instance, if the two tubal structures fail to unify, a “bicornuate” uterus develops. In other words, the result is a uterus with two separate horns. If the septum is not resorbed, then the result is a septate uterus. In addition, the uterus growing down from above must unify with the vaginal tube growing from below. If these two structures do not unify normally, then a transverse vaginal septum is the result.

This is an example of an obstructive abnormality, since the menstrual blood from the uterus cannot escape into the vagina. The accumulation of this blood will cause the patient to experience pain. Because of the significant pain symptoms, obstructive abnormalities will almost always be treated surgically. Once the obstruction is removed, the patient will then be able to menstruate normally and will no longer have the pain symptoms.

Non-obstructive abnormalities may be repaired surgically if they cause abnormal pregnancy and miscarriage. If it is possible, the uterus will be normalized surgically.

The most common example of an abnormality that has a high association with pregnancy loss and is easily repaired is the uterine septum. This is like a wall that divides the uterus into two sides. Using a hysteroscopy, a lighted tube with a cutting device, the reproductive surgeon can divide the septum in less than 30 minutes and completely normalize the uterine cavity. This generally will markedly improve the woman’s chances for delivering a healthy baby.

Women are encouraged to seek help from a reproductive endocrinologist if she has had multiple pregnancy losses, and if she has a known uterine abnormality.