What Is a Bicornuate Uterus?

In some cases. a bicornuate uterus may cause complications during pregnancy

Patient lying on examination table during examination
Getty Images/Angela Wyant

A bicornuate uterus is a type of congenital uterine malformation (müllerian duct abnormality). A bicornuate uterus is heart-shaped with two conjoined cavities. A typical uterus only has a single cavity. A bicornuate uterus is just one of several types of müllerian duct anomalies. Other types include uterus didelphys (two separate uteri), unicornuate uterus (only one duct is present, resulting in a smaller-than-average uterus), and septate uterus (the uterus is divided by a wall or septum).

A bicornuate uterus is the most common müllerian duct anomaly.

A bicornuate uterus results from the uterus improperly forming during a woman's early prenatal development. This can happen to women whose mothers took a medication called diethylstilbestrol (DES) while pregnancy or for other, unknown reasons.

How Do You Know If You Have a Bicornuate Uterus?

Doctors can get an idea of whether a woman has a bicornuate uterus through a standard ultrasound or by using a hysterosalpingogram (HSG) or a hysteroscopy. In some cases, the diagnosis should be confirmed with a three-dimensional ultrasound or laparoscopy.

Most women do not know they have a bicornuate uterus until they are pregnant or trying to get pregnant. Menstruation, in most cases, is normal.

Bicornuate Uterus and Pregnancy Loss

The primary risks associated with a bicornuate uterus is preterm labor and possible cervical insufficiency (not first-trimester miscarriages).

Cervical insufficiency and preterm delivery could potentially cause a second-trimester miscarriage or pregnancy loss at birth if the baby is born too prematurely –– before 24 or 25 weeks of pregnancy (the point at which a premature baby can potentially survive). Because of the indentation on the top of the uterus, a developing fetus may not have enough room to grow.

This can also result in preterm labor.

However, many women with bicornuate uteri carry pregnancies to full term without any problems. Therefore, the risk for each woman varies.

Treating a Bicornuate Uterus

Some physicians might recommend reconstructive laparoscopic surgery if you have bicornuate uteri. In most cases, doctors do not suggest surgical treatment. Some women may need a cervical cerclage, a stitch placed in the cervix to stop premature dilation. This procedure prevents premature delivery and possible late pregnancy loss. Treatment depends on the physician and the circumstances of the situation.

For women with recurrent miscarriages, it is important to consider that some women diagnosed as having bicornuate uteri, actually have septate uteri. The two congenital uterine malformations can look similar on imaging studies, such as HSG or ultrasound. A septate uterus is round on the top with a single cavity and a bicornuate uterus dips on the top, forming a heart shape with two cavities.

A bicornuate uterus might not be treated, except to watch for signs of cervical dilation. If it is treated surgically, a reconstruction will be done via laparoscopic surgery. A septate uterus is usually treated through a hysteroscopic surgery. A bicornuate uterus is not usually considered a factor in recurrent miscarriages, whereas a septate uterus is known to increase miscarriage risks.

If you are having recurrent miscarriages and your doctor has determined you have a bicornuate uterus, consider seeing a specialist for a second opinion to confirm your diagnosis and discuss treatment plans.


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