Uterine abnormalities that cause infertility or pregnancy losses
Uterine abnormalities can be either congenital (i.e. something you are born with) or they can develop over time.
Uterine abnormalities that are present from birth.
Congenital abnormalities of the uterus and fallopian tubes that are present at birth, are called Mullerian anomalies. These abnormalities result from abnormal development of the uterus, fallopian tubes, or cervix. During early fetal development, the uterus actually starts out as two separate parts in the upper abdomen. Each portion migrates down into the pelvis and joins together to fuse with what will eventually become the vagina. The uterus at that point is solid. The cavity of the uterus, where a baby eventually implants, develops several days later. Once a normal uterine cavity develops, it takes on a triangular shape.
If this process does not happen correctly, many different possible outcomes (called Mullerian anomalies) can result.
Common Mullerian abnormalities
septate uterus – when the middle wall that joins the two uterine cavities fails to completely reabsorb. This leaves a single uterine cavity with a defect remaining at the top. This defect can vary in size from very small to one that comes all the way down to the cervix – completely dividing the uterine cavity in two.
bicornuate uterus – when the two uterine cavities join only at the bottom (i.e. at the cervix). The upper portions of the uterus are clearly separate. In this situation, there can either be one cervix or two cervices
unicornuate uterus – when one side of the uterus does not develop at all, so the ultimate uterus is about half the normal size
uterine didelphys – when the separate parts of the uterus don’t join at all, resulting in two completely separate uterine cavities and two cervices
Each of these abnormalities is associated with both infertility and recurrent pregnancy loss. Only a septate uterus can be surgically repaired, and clinical data suggest that repair results in both significantly higher pregnancy rates and significantly lower miscarriage rates. None of the other types of Mullerian anomalies should be repaired, as the “fix” may be worse than the actual condition itself.
Uterine abnormalities acquired over time
There are a few other uterine abnormalities that develop over time. These include uterine fibroids, uterine polyps and uterine adhesions (scarring in the cavity).
These uterine abnormalities can cause symptoms such as pain during menstruation, heavy periods, irregular bleeding, pain with sex, and even frequent urination or constipation. Sometimes there are no symptoms at all, and these uterine abnormalities are found on a routine ultrasound. Imaging such as a saline sonogram or hysterosalpingogram (HSG) can identify these uterine abnormalities.
If you have any questions, please contact our San Antonio fertility center.