What Is A Unicornuate Uterus?
The uterus, fallopian tubes, cervix, and part of the vagina are formed from the so-called Müllerian ducts in female embryos. These ducts normally connect at around 10 weeks gestation, but when something goes wrong with that process — as it does in approximately 0.1 to 3.8 percent of the female population — you end up with a uterine abnormality.
Uterine malformations come in different shapes. Think of the normal uterus as an upside-down triangle, the tops of which connect to the fallopian tubes. These portions are sometimes called "horns". Uterine abnormalities include:
- A septate uterus, in which the two halves of the uterus are separated by a band of tissue.
- A bicornuate uterus, in which a single uterus has two separate "chambers".
- A didelphic uterus, in which a woman essentially has two small uteri, each with their own cervix or opening into the vagina.
A unicornuate uterus is the rarest of all uterine abnormalities. In women with a unicornuate uterus, the uterus is shaped more like a banana than a triangle. It is smaller than usual because one of the Müllerian ducts didn't develop or didn't develop well. As with other kinds of uterine abnormalities, there are several different sub-types of unicornuate uteri. Some women with a unicornuate uterus possess a "rudimentary horn" on the underdeveloped side, and this rudimentary horn sometimes "communicates" with the rest of the uterus, in terms of the growth of endometrial (uterine lining) tissues.
Women who have a unicornuate uterus may not be aware of the condition unless they experience difficulty conceiving or abdominal pain, or they seek medical attention from an OBGYN during which the condition is revealed — because they are pregnant, for instance.
Because a unicornuate uterus is so rare, it is both hard to find reliable information about the condition online, and hard to obtain adequate information from your doctor, who may not have encountered a unicornuate uterus before.
Can I Get Pregnant And Stay Pregnant With A Unicornuate Uterus?
Research suggests that:
- 30 percent of women with a unicornuate uterus who get pregnant will experience a live birth.
- 44 percent of babies born to mothers with unicornuate uteri will be delivered prematurely.
- 4 percent of pregnancies experienced by women with a unicornuate uterus are ectopic.
Pregnancy complications that are seen significantly more often in women with unicornuate uteri include miscarriages during the first and second trimesters of pregnancy, intrauterine growth restriction (IUGR), premature birth, and breech babies. These complications are linked to the fact that women with unicornuate uteri have decreased blood flow to the uterus, as well as a lower muscle mass and a weaker cervix. You also have a higher chance of infertility if you have a unicornuate uterus, and are more likely to need a c-section.
Scientific analysis showed, however, that women with the so-called "communicating" subtype of unicornuate uterus are much more likely to get pregnant naturally and to stay pregnant.
The Bottom Line
Your chances of getting pregnant and having a baby depend on the kind of unicornuate uterus you have, but women with unicornuate uteri do get pregnant and go on to have healthy babies. If you have a "communicating" unicornuate uterus, your chances of success are highest. You may, in your search for information, be frustrated by the fact that so little information is available about your condition. Your best bet lies in finding a doctor who has experience in working with women with unicornuate uteri.
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