by TeamWinks and Serenity
What a Uterine Anomaly Means and Its Impact on Fertility
A uterine anomaly is a form of congenital birth defect - in that the uterus forms when the fetus is inside her mother's womb.
About ten weeks after conception, the uterus is comprised of a pair of structures called mullerianducts. The top of the ducts (i.e. the ones closest to the embryo's head) will become the fallopian tubes - they remain separated throughout development.The bottom of the mullerian ducts, however, begin to fuse together to become one structure that will become the uterus. At stage one of this fusion, they have formed a central wall, or "median septum" in the middle of the fused tube. This structure, when first formed, is a cylindrical structure of equal diameter.
Between ten and thirteen weeks, the central wall of this tube begins to expand at the top to form the uterus fundus. At the bottom of the uterus, this central wall, or median septum also begins to dissolve; leaving a continuous chamber that will become the uterine cavity.Between weeks thirteen and twenty, the median septum should dissolve completely from the bottom to the top of the uterus, resulting in a single, continuous uterine cavity.
Uterine anomalies result from the following:
- failure of one of the two mullerian ducts to form (unicornuate),
- failure of the two ducts to fuse completely (bicornuate), or
- failure of the two fused mullerian ducts to dissolve the median septum (septate).
Some uterine abnormalities can be diagnosed with a simple ultrasound - a bicornuate uterus, for example, sometimes clearly shows two uterine cavities (or "horns.") However, once a uterine abnormality is identified, it does take some work to fully diagnose it. The best method of diagnosis is generally a hysteroscopy and/or laparoscopy, but that requires the use of generalanesthesia and is generally more expensive.
A HSG & Saline Infusion Ultrasound, where they fill your uterine cavity with fluid/dye can give your RE a good idea of what type of abnormality exists. Your RE may want to perform a MRI, CT scan, and/or 3D ultrasound as well.
Treatment Options and Prognosis
Treatment of a uterine abnormality is entirely dependent on which type of diagnosis you receive and your RE. Generally, however, a septate uterus will present fertility issues in that the septum has no blood flow and will sometimes interfere with the implantation process. In that case, a hysteroscopy and laparoscopy will be recommended, where your RE will surgically remove the septum. Depending on its size, you may need multiple procedures. Unicornuate and bicornuate uterus diagnoses will often not be treated at all, since with both types there tends to be a normal blood flow to the uterus. However, there is an increased chance of preterm labor - since the uterus doesn't stretch like a "normal" uterus would. Thus, when a woman with this type of anomaly becomes pregnant, some doctors classify them as high risk.
Once you learn that you have a uterine anomaly, you can expect a whole lot of confusion. It is often very difficult to pin down exactly what your uterus looks like. Reproductive outcomes for women with these anomalies aren't all that reassuring, and it certainly doesn't help that there is a lack of literature out there to educate yourself. Be prepared to primarily read literature that was prepared for other doctors and not the average woman. They are often dense articles, and take time to work through. There is a wonderful support group on yahoo that does help (http://health.groups.yahoo.com/group/MullerianAnomalies/)
I am not sure whether I have a bicornuate uterus or a unicornuate uterus. My RE has been unable to pin this one down. Soon we should know for sure. I would say on a good day that having this birth defect can be difficult. Often women with a uterine anomaly have only one kidney. Thankfully I have two. They also have high incidences of PCOS, endometriosis, insulin resistance, high miscarriage rates, and pre-term labor. That's a strong cocktail thrown at you at once. I truly believe you need a support system from the moment the diagnosis is handed to you. It's important to remember that it isn't a death sentence. However, it is important to ask as many questions as you can.
My RE thinks that I have a true bicornuate uterus, which was diagnosed last year after my hysteroscopy. But given our recent IVF failures and that we believe it might be implantation related, we are revisiting this at the end of the month, however, with a 3D ultrasound to ensure that he didn't miss a septum earlier. The biggest thing to remember: the statistics and risks they throw at you when you're diagnosed are often skewed. There are a lot of women who a have bicornuate/unicornuate uterus who have never been diagnosed; they have gone on to get pregnant and have perfectly normal pregnancies and healthy babies. My OB and my RE told me that having a bicornuate uterus was probably the "best" one to have, practically speaking, since I have good endometrial lining in both horns. They have also told me that the bulk of women who have this to go on and bear very healthy, normal children. So my advice would be to take the risks you'll read about with a grain of salt.
Links for uterine anomaly research:
In addition, Preventing Miscarriage by Jonathan Scher has some information about uterine anomalies and their role in miscarriage.