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A unicornuate uterus is a rare congenital uterine malformation. Around two to eight percent of women with infertility are diagnosed with unicornuate uterus. However, there is hope because women with a unicornuate uterus can become pregnant and deliver healthy babies.
What is Unicornuate Uterus?
In this complication, the uterus does not develop completely and has only one fallopian tube instead of the normal two. It looks like a single, rudimentary horn. The uterus is also smaller than a normal uterus. It may be disconnected from other parts of the womb and is hence unable to drain out menstrual fluid. It may also be connected with the rest of the uterus or may contain a functional endometrium. In certain cases, the uterus may develop a smaller offshoot called a hemi-uterus.
What Causes Unicornuate Uterus?
A unicornuate uterus is caused due to an abnormal müllerian duct or paired duct of the embryo. This is congenital i.e. women are born with it.
Symptoms of Having Unicornuate Uterus
This condition can be asymptomatic when there is a hemi-uterus with a small cavity and a functional endometrium. It is asymptomatic because the cavity forms a connection with the uterus and the vagina and drains out the menstrual fluid. So, there is no abdominal/pelvic pain or discomfort. This occurs in 65% of women and the condition may remain totally undetected till the woman faces difficulty in conceiving. In such cases, unicornuate uterus treatment becomes delayed.
But in many cases the horn does not connect to the uterine cavity, resulting in these symptoms:
- Chronic pelvic or period-time abdominal pain: This can occur in cases where the functioning horn is solid and isolated from the rest of the uterus. The pain occurs because of a build-up of menstrual fluid that cannot drain out through the vagina.
- Hematometra: This is the accumulation or retention of blood in the uterus because of its inability to drain out fluids. The symptoms are cramping pain during periods in the lower abdomen and pelvic midline, frequent urination, and urinary retention. Women in pre-menopause may also report abnormal bleeding or no menstruation at normal cycles. The build-up of blood may also cause low blood pressure or a vasovagal issue. However, women in menopause may be asymptomatic.
- Endometriosis: This is a disorder in which the tissue that normally lines the interior of the uterus (called the endometrium) is found to grow outside the uterus. It involves a lot of severe, sharp, nagging pain in the lower abdomen that does not go away with medication. Often surgery is required as treatment.
- A history of infertility.
- Premature birth, miscarriage, and breech baby.
How Is The Diagnosis Done?
This condition remains undiagnosed until a woman suffers from pregnancy complications like a history of infertility, repeated miscarriages, or premature delivery.
There are some tests that may also detect the problem and facilitate timely treatment:
- Infertility and/or regular pelvic tests: Unicornuate uterus maybe suspected during these tests. Detection is usually rare in these tests.
- Imaging: A normal ultrasound often fails to diagnose a unicornuate uterus. An MRI, which is a three-dimensional sonography, has better results.
- Laparoscopy: This can confirm the problem.
- Hysteroscopy: This is a process in which a miniature telescope is inserted via the cervix to view the uterus for diagnosis or treatment of certain conditions. This can also detect a unicornuate uterus.
Unicornuate Uterus and Pregnancy
Reproductive complications are common in women with a unicornuate uterus. Pregnancy in unicornuate uterus women is difficult because usually only one fallopian tube functions in this situation. Even if they become pregnant unicornuate uterus involves the following risks:
- Miscarriage: There maybe foetal demise and stillbirth because of the abnormal shape of the uterus and inadequate blood flow to the uterus and placenta that feeds the foetus.
- Premature birth: Women with unicornuate uterus may go into early labour because the baby outgrows the uterine space that is smaller than usual. This happens in the first stages of pregnancy. It increases the chances of a breech birth as well, where the baby is born ‘bottom first’ instead of the normal ‘head first’. This can lead to a cesarean (C-section) instead of a normal delivery.
- Ectopic pregnancy: Women with unicornuate uterus may witness an ectopic pregnancy. This occurs when a fertilized egg implants outside the uterus, typically in the fallopian tube. Unfortunately, the pregnancy must be terminated.
- Heavy bleeding: This could pose a life threat because of a premature rupture of membranes during the first or second trimester.
- Intrauterine growth retardation: Here the newborn may be smaller in weight and size.
- Placenta previa: When you conceive, the placenta normally attaches to the upper part of the uterus, leaving the cervix free. In placenta previa, it attaches to the lower part of the uterus, spreading to the entire or part of the cervix.
- Placental abruption: Here the placenta gets suddenly detached from the uterus, usually after the 20th week of pregnancy. If this is severe and undetected it may result in a stillborn or premature baby.
- Intrauterine foetal demise: This means a stillborn baby.
- Abdominal pain and collapse: Even if women with unicornuate uterus undergo highly advanced procedures, detection may be delayed. By then it may be too late and result in collapse.
Does Unicornuate Uterus Have Any Impact on Fertility?
Unicornuate uterus causes significant gynaecological and obstetrical complications. This has a major impact on fertility. Women are rarely able to conceive when there is a rudimentary horn. Even if they manage to conceive, there are various risks involved like uterine rupture during the first or second trimester that triggers heavy bleeding and could pose a life-threat to the mother as well as the foetus that may be terminated. Unicornuate uterus impacts fertility of women at the exact rate given below:
- Live birth: 29.2%
- Prematurity: 44%
- Ectopic pregnancy: 4%.
- First trimester abortion: 24.3%
- Second trimester abortion: 9.7%
- Intrauterine fetal demise:10.5%.
Unicornuate uterus treatment is never fully effective because the uterus cannot be enlarged surgically. These surgical and non-surgical procedures are the most accepted methods to simply manage the condition:
- Cervical stitch or cerclage: This is often suggested in unicornuate uterus cases that report a history of miscarriages, premature delivery and incompetent cervix. In this procedure, the cervix is stitched and closed during pregnancy.
- Laparoscopic surgery: This is conducted to remove an isolated hemi-uterus because it causes abdominal pain due to the accumulation of menstrual blood that cannot flow out.
- Emergency delivery under special care: Pregnancy is possible in a non-communicating uterus as explained earlier in the article. However, this poses greater risks to pregnant women and could involve an emergency situation because the uterus may rupture by the end of the second trimester due to space constriction in a smaller uterus. Utmost care and caution should be taken to avoid risks to the mother and the baby. This happens in an estimated 89% of cases. To avoid this, doctors recommend a laparoscopy to the remove the isolated hemi-uterus. We have discussed this process in the preceding point.
Usually, though, no surgical intervention is recommended unless endometrial tissue in the rudimentary horn causes pain or a pelvic mass. A solid non-functioning hemi-uterus also need not be removed surgically.
Finally, the type of treatment depends a lot on the variations in the unicornuate uterus. The condition of the uterus varies from case to case. For instance:
- A rudimentary horn may or may not be present.
- The horn may or may not connect to the rest of the uterus.
- The size of the uterus can also vary.
One of the most accepted treatment is unicornuate uterus IVF with embryo transfer. eSET (elective single embryo transfer) can reduce the high risk associated with multiple pregnancies (uterine breach or rupture) with a singleton pregnancy in women with a unicornuate uterus. If a miscarriage occurs repeatedly, surrogate motherhood can be considered.
This condition may be very complex, but the good news is that many women (half of them as reported in research done) have given birth to full-term healthy babies and even twins! Complications can be managed and averted with careful and advanced medical care.
Also Read: List of 10 Different Types Of Pregnancy