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DEAR MAYO CLINIC: I am 36 and have had two miscarriages in the past six months. I went to my doctor for tests and found out that I have a double uterus. My doctor said that I should still be able to carry a baby to term and that having a double uterus isn’t necessarily the cause of the miscarriages. Is there a way to find out if the double uterus really is causing my miscarriages? When is surgery considered for someone in my situation?
ANSWER: When a woman’s uterus is shaped differently than normal, as with a double uterus, it may increase the risk of pregnancy loss. But many women who have uterine abnormalities are able to get pregnant and have a normal pregnancy and delivery. In your situation, additional tests can show the specific structure of your uterus. The results of those tests can help your doctor identify if you may need treatment such as surgery to decrease your risk of another pregnancy loss.
During a fetus’s growth and development, the uterus normally starts as two separate spaces and then they merge into one. In women who have a double uterus, the two did not merge during fetal development. Instead, they sit side-by-side. In another common situation, the two uterine cavities do join together, but development is incomplete. The two sections of the uterus are separated by a layer of tissue called a septum. This is called a septate uterus.
In a situation such as yours where there has been two pregnancy losses, it is important to investigate if you have a double uterus where the cavities are completely separate, or if you have a septate uterus. This evaluation can be done with an ultrasound exam or magnetic resonance imaging (MRI). Your doctor also may use a test called a sonohysterogram. It involves putting water into the uterus, and then looking at it with an ultrasound. This test often provides better images than ultrasound alone, allowing your doctor to take precise measurements of the uterus.
If tests show you have a septate uterus, that could be contributing to the miscarriages. A septum between uterine cavities may not have adequate blood supply to sustain an embryo. That means if an embryo implants upon it, there may be an increased chance for pregnancy loss.
The septum can be removed with a simple surgical procedure. The uterus is filled with fluid, usually saline solution, to enlarge it. The doctor then goes through the vagina with small surgical scissors and trims away the septum. Once the septum is removed and the uterus heals after the procedure, it typically offers a better environment for an embryo to implant and grow. To allow that healing to take place, doctors suggest women wait for two to three menstrual cycles after the procedure before trying to become pregnant.
If you have a double uterus and the two cavities are completely separate, your miscarriages are less likely to be due to uterine structure. But your risk of pregnancy complications may be higher than normal. For example, you may have an increased risk of bleeding in the latter portion of pregnancy. That bleeding usually is minor, though, and generally does not endanger a pregnancy. Because the size of the individual uterine cavities is smaller than a typical uterus, a double uterus also can raise the risk of early delivery and, in some cases, may require delivery by Cesarean section.
Although abnormal uterine shapes may cause some difficulties with pregnancy, many other factors can lead to pregnancy loss, as well. These include genetics, hormone deficiencies and underlying medical conditions, among others. It would be a good idea to talk to your doctor about all the possible causes of your miscarriages before you move forward with any treatment or before you make a decision about becoming pregnant again. — Charles Coddington III, M.D., Reproductive Endocrinology and Infertility, Mayo Clinic, Rochester, Minn.