What is a bicornuate uterus and does it affect pregnancy?

If you’ve been told you have a bicornuate uterus (also known as a “heart-shaped uterus”), you likely were pretty surprised since most women with this condition don’t experience any symptoms. But now, you might be wondering if this diagnosis could impact your reproductive health or ability to have a baby. Here’s what you should know about this condition and its impact on pregnancy. 

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A bicornuate uterus is a congenital uterine malformation, meaning the uterus developed abnormally before birth. If you have a bicornuate uterus, it's something you were born with and have had all your life—you did not do anything to cause this to happen (Kaur, 2021). 

The uterus (also called the womb) is the hollow organ where a baby develops and grows. Usually, the uterus looks like an upside-down pear. A bicornuate uterus is heart-shaped—with an indentation at the top—creating two separate but connected sections (Kaur, 2021). 

A bicornuate uterus is a relatively rare condition, affecting four out of 1000 women (Kaur, 2021). 

Most people with a bicornuate uterus don’t have any symptoms. Women often discover they have the condition once they become pregnant and go for an ultrasound. However, some women may experience the following (Kaur, 2021):

• Heavy menstrual bleeding

• Bleeding that lasts longer than seven days

• Severe pain or cramps during their periods 

• Multiple miscarriages 

If you’ve been diagnosed with a bicornuate uterus, you may wonder how this condition will impact your plans for starting a family. A bicornuate uterus does not affect your ability to get pregnant. It can, however, lead to some adverse pregnancy outcomes, although many women can have successful pregnancies. Your healthcare provider will monitor your pregnancy closely to ensure you and your baby remain healthy (Bhagavath, 2017). 

People with a bicornuate uterus are at an increased risk of miscarriage. Some studies report the rate of pregnancy loss in the first and second trimesters to be as high as 36% (Bhagavath, 2017). This may result from the cervix dilating or thinning too soon, the uterus not expanding correctly, or increased inflammation (Turocy, 2019). Preterm delivery (going into labor before 37 weeks of pregnancy) is also typical (Bhagavath, 2017). 

A bicornuate uterus can limit how well your baby grows, decreasing its size and birth weight. The abnormal shape of the uterus also affects the position of the baby at the time of delivery. There is an increased chance of the baby being breech (positioned at delivery with feet down instead of head down) or in another position that is not ideal for vaginal delivery. For this reason, women with a bicornuate uterus are more likely to require a cesarean section (c-section) (Kaur, 2021). 

These potential risks do not need to be a reason to avoid getting pregnant. Your healthcare provider will support you through your pregnancy, helping increase your chances of having a healthy pregnancy and baby.

A bicornuate uterus occurs when female babies are developing in the womb. Two separate tubes (called the paramesonephric ducts or Müllerian ducts) fuse to form the uterus. Any disruption in this process can result in a congenital uterine anomaly (Kaur, 2021). 

A bicornuate uterus occurs when the tubes only partially fuse. This leaves the top part of the uterus as two separate sections that connect at the bottom (hence the name “heart-shaped uterus”). Researchers don’t know for sure why this happens (Kaur, 2021). 

Your healthcare provider may perform one or more of the following tests to determine if you have a bicornuate uterus or other uterine condition (Kaur, 2021):

• Ultrasound: An ultrasound is the most common test used to diagnose a bicornuate uterus. Most people discover they have the condition while having an ultrasound performed during pregnancy. Others may have an ultrasound done to investigate the cause of recurrent pregnancy loss or menstrual symptoms, such as excessive bleeding or pain (Kaur, 2021).

• Magnetic resonance imaging (MRI): MRI provides the most accurate information and can help diagnose cases that may be unclear on ultrasound (Zafarani, 2017). 

• Hysterosalpingography: During a hysterosalpingogram, fluid containing a dye is infused into the uterus. This allows X-ray images to visualize the inside shape of the uterus and fallopian tubes. Your healthcare provider may recommend hysterosalpingography if you’re struggling with infertility, have abnormal bleeding, or have symptoms of uterine fibroids (Zafarani, 2017). Hysterosalpingography can detect uterine abnormalities, but it may not differentiate between types, such as a bicornuate uterus and septate uterus. In this case, your healthcare provider may suggest additional testing (Kaur, 2021). 

Most people with a bicornuate uterus don’t have any symptoms, but be sure to contact your healthcare provider if you experience (Kaur, 2021):

• Irregular or excessive bleeding 

• Painful periods

• Recurrent miscarriages 

There’s isn’t a specific treatment usually recommended for a bicornuate uterus. Instead, if you become pregnant, you will be closely monitored by your healthcare provider (Kaur, 2021). 

Having a bicornuate uterus may cause cervical weakness (also called cervical insufficiency). This might cause the cervix to dilate or thin out too early and can result in preterm birth. Your healthcare provider may recommend something called a cervical cerclage (also known as a cervical stitch). During this procedure, your healthcare provider will place a stitch around your cervix to strengthen it. One study showed cervical cerclage in women with bicornuate uteri can greatly decrease the chances of miscarriage, leading to full-term pregnancies in 76% of participants, compared with 27% who did not have a cervical cerclage placed (Bhagavath, 2017). 

Surgery is not typically recommended for most people with a bicornuate uterus, but if you’ve experienced repeated miscarriages or preterm labor, it may be an option. A surgical procedure called Strassman metroplasty works by connecting the two separate portions of the uterus to make one uterine cavity (Kaur, 2021). 

Finding out you have a bicornuate uterus can leave you feeling worried about your reproductive health. Talk to your healthcare provider about your options. While you may experience some challenges, many women have successful pregnancies with the proper care.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

September 02, 2021

Written by

Christina Varvatsis, PharmD

Fact checked by

Steve Silvestro, MD

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About the medical reviewer

Steve Silvestro, MD, Ro

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.