Bicornuate Uterus: The Heart-Shaped Womb You're Born With — and Why Many People Still Have Healthy Pregnancies
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD. Last reviewed October 13, 2026. This content is for educational purposes and is not medical advice.
Quick Answer
A bicornuate uterus is a heart-shaped uterus, dipping down at the middle of the top, that a person is born with [1]. About 0.4% of girls have one [1]. It often causes no symptoms but can lead to frequent miscarriages and painful periods [1]. Fertility usually is not affected, and many people have healthy pregnancies with closer monitoring [1].
What the research says
Fertility is usually preserved, but some pregnancy risks go up. A systematic review of 9 studies including 3,805 women found that "unification defects," a group that includes bicornuate uterus, did not reduce fertility but were linked to more preterm birth (risk ratio 2.97, 95% CI 2.08 to 4.23) and more fetal malpresentation, such as a breech baby (risk ratio 3.87, 95% CI 2.42 to 6.18) (Chan et al., Ultrasound Obstet Gynecol, 2011) [3].
Preterm birth is the most common concern. In a meta-analysis of 32 cohort studies, congenital uterine anomalies as a group raised the odds of preterm birth (adjusted odds ratio 4.34, 95% CI 3.59 to 5.21) and first- or second-trimester miscarriage (odds ratio 1.54, 95% CI 1.14 to 2.07). Bicornuate uterus was associated with the highest number of adverse outcomes among the types compared (Caballero Campo et al., Facts Views Vis Obgyn, 2024) [4].
Fertility treatment results look similar. A systematic review of 55 studies on assisted reproduction found that a bicornuate uterus did not seem to worsen the outcomes of fertility treatment (Fedele et al., Arch Gynecol Obstet, 2024) [5].
What Is a Bicornuate Uterus?
A bicornuate uterus is a uterus that's shaped like a heart. It's a condition you're born with that may or may not cause symptoms.
A typical uterus is shaped like an upside-down pear. The wide, round part of the pear resembles the top portion of the uterus. If your uterus is bicornuate, the top of your uterus dips down at the middle, making it look like a heart [1].
A typical uterus is one hollow cavity. It's made to expand during pregnancy. If you have a bicornuate uterus, the top of your uterus is separated by a piece of tissue. This can cause problems during pregnancy because your uterus may not expand [1].
It's a condition you're born with. Most people won't know they have one until they have several miscarriages or a pregnancy complication. If you become pregnant with a bicornuate uterus, there's an increased risk of preterm labor and other pregnancy complications. About 0.4% of girls are born with a bicornuate uterus [1].
What Are the Symptoms of a Bicornuate Uterus?
Symptoms could include frequent miscarriages (usually more than three), painful menstruation, painful sex, and pelvic pain [1].
In some cases, you may not realize you have a heart-shaped uterus because you don't have symptoms. Or you could have symptoms, but they may seem normal to you because you don't know any differently.
Symptom | What it looks like |
Frequent miscarriages | Usually more than three |
Painful menstruation | Painful periods |
Painful sex | Pain during intercourse |
Pelvic pain | Discomfort or pain in the pelvis |
What Causes a Bicornuate Uterus?
You're born with a bicornuate uterus. The uterus develops in a fetus around week 12 of pregnancy [1]. During development, the Müllerian ducts normally fuse to form one uterine cavity. With a bicornuate uterus, the ducts don't merge. Experts aren't completely sure why this happens.
What Are the Two Types of Bicornuate Uterus?
Your provider may describe your bicornuate uterus as either partial or complete. These terms refer to how far your uterus dips down at the top [1].
Type | Description |
Partial bicornuate uterus | A smaller separation between the two cavities; your uterus is still heart-shaped, but the indentation that divides it is mild |
Complete bicornuate uterus | A severe indentation at the top of the uterus; this makes the separation more distinct |
What Are the Complications and Pregnancy Risks?
You have a higher risk of endometriosis if your uterus is irregularly shaped [1]. But there aren't any serious complications of a bicornuate uterus outside of pregnancy. You won't be able to use an intrauterine device for birth control due to the shape of the cavity [1].
If you're pregnant and have a bicornuate uterus, you're at a higher risk for miscarriage, preterm labor, intrauterine growth restriction (IUGR), a breech baby, C-section, postpartum hemorrhage, and placenta previa [1].
How Is a Bicornuate Uterus Diagnosed?
Most people aren't aware they have a bicornuate uterus until they have several miscarriages. Your healthcare provider may discover the condition while they're looking for the cause of the miscarriages or preterm labor. Sometimes, your provider may find a heart-shaped uterus during a routine prenatal ultrasound or because of painful periods [1].
After a pelvic exam, they'll use several imaging tests to diagnose a bicornuate uterus. An ultrasound is usually the first test your provider uses to detect a heart-shaped uterus [1]. An MRI produces the most detailed images of your uterus because it can show multiple dimensions and angles. Hysterosalpingography is an X-ray that uses a special dye to fill in your uterine cavity — it can show the shape of your uterus and how deep the indentation is [1].
Test | What it shows |
Pelvic exam | The starting exam before imaging |
Ultrasound | Usually the first test to detect a heart-shaped uterus |
MRI | The most detailed images, showing multiple dimensions and angles |
Hysterosalpingography | An X-ray with special dye that shows the uterine shape and how deep the indentation is |
What Are the Treatments for a Bicornuate Uterus?
Surgeons can treat a bicornuate uterus with a procedure called metroplasty. During the procedure, they reshape your uterus by removing the tissue that causes the heart-shaped appearance. But surgery usually isn't necessary — it's typically only for people with repeat miscarriages or a history of pregnancy complications [1].
Many people with the condition have no symptoms and can have a healthy pregnancy without surgery [1]. Your pregnancy care provider may just monitor you more during your pregnancy. You'll likely have more prenatal ultrasounds [1]. This is so your provider can see the size and shape of your uterus, the fetus, and the placenta.
If your provider recommends surgery, they'll explain the procedure, its risks, and your chances of having a successful pregnancy afterward.
Can You Get Pregnant With a Bicornuate Uterus?
Yes, you can get pregnant. Fertility usually isn't affected. But the shape of your uterus puts you at a slightly higher risk for pregnancy complications [1]. Your healthcare provider will discuss any precautions you should take during pregnancy.
Are Labor and Delivery Affected?
Maybe. Your uterus may not expand as much as a typical uterus. This could lead to preterm labor or the fetus being in a breech position [1]. Your pregnancy care provider may recommend a C-section delivery if this is the case. You're also at a higher risk of postpartum hemorrhage [1].
When Should You Call a Healthcare Provider?
Contact a healthcare provider if you experience pelvic pain during your period or during sex [1]. These could be signs of an underlying condition.
If you're pregnant with a bicornuate uterus, contact your healthcare provider immediately if there are any signs of labor — like contractions or your water breaking [1].
Some questions to ask your healthcare provider about this condition include:
What health complications should you be aware of?
What are the risks of being pregnant with a bicornuate uterus?
Will your baby be born healthy?
Should you have surgery to fix it?
What's the Bottom Line?
A bicornuate uterus is a heart-shaped womb you're born with — the top dips down at the middle instead of staying round like the top of an upside-down pear. About 0.4% of girls are born with one [1], and most never find out until several miscarriages or a pregnancy complication. The cause traces back to week 12 of fetal development, when the two structures that should fuse into one uterine cavity don't merge — and experts aren't completely sure why. Symptoms can include frequent miscarriages, painful periods, painful sex, and pelvic pain, but many people have no symptoms at all. Diagnosis starts with a pelvic exam, then ultrasound, MRI, or hysterosalpingography, and the condition comes in partial and complete forms. Surgery (metroplasty) exists but usually isn't necessary; many people have healthy pregnancies with nothing more than closer monitoring and extra ultrasounds [1]. Fertility usually isn't affected. If you're pregnant with a bicornuate uterus, call your provider right away at any sign of labor — contractions or your water breaking — because preterm labor is a real risk. Open conversation with your provider is the best next step.
Don't leave questions unanswered. If you've had several miscarriages, painful periods, or a pregnancy complication, a simple imaging test can reveal what's really going on — start the conversation with a trusted healthcare provider. Explore more clear, practical health guides at Rinnit.com.
Frequently Asked Questions
What is a bicornuate uterus?
A uterus that's shaped like a heart. The top dips down at the middle instead of staying rounded like the top of an upside-down pear.
Is a bicornuate uterus something you're born with?
Yes. It's a condition you're born with that may or may not cause symptoms.
How common is a bicornuate uterus?
About 0.4% of girls are born with one.
What are the symptoms of a bicornuate uterus?
Frequent miscarriages (usually more than three), painful menstruation, painful sex, and pelvic pain — but some people have no symptoms at all.
Why do some people have no symptoms?
You may not realize you have a heart-shaped uterus because you don't have symptoms, or your symptoms may seem normal to you because you don't know any differently.
What causes a bicornuate uterus?
Around week 12 of fetal development, the Müllerian ducts normally fuse to form one uterine cavity. With a bicornuate uterus, the ducts don't merge — experts aren't completely sure why.
What's the difference between partial and complete bicornuate uterus?
A partial bicornuate uterus has a smaller separation between the two cavities with a mild indentation. A complete bicornuate uterus has a severe indentation at the top, making the separation more distinct.
Does a bicornuate uterus affect fertility?
Usually not. You can get pregnant, and fertility usually isn't affected — but the shape of your uterus puts you at a slightly higher risk for pregnancy complications.
Can you have a healthy pregnancy with a bicornuate uterus?
Yes. Many people with the condition have no symptoms and can have a healthy pregnancy without surgery, with closer monitoring and more prenatal ultrasounds.
What pregnancy complications are more likely?
Miscarriage, preterm labor, intrauterine growth restriction (IUGR), breech baby, C-section, postpartum hemorrhage, and placenta previa.
Does a bicornuate uterus cause serious problems outside of pregnancy?
No. There aren't any serious complications outside of pregnancy, though an irregularly shaped uterus carries a higher risk of endometriosis, and the shape of the cavity means you can't use an intrauterine device (IUD) for birth control.
How is it diagnosed?
After a pelvic exam, providers use imaging tests — usually ultrasound first, then MRI (the most detailed) and hysterosalpingography (an X-ray with special dye that shows the shape and depth of the indentation).
What is metroplasty?
A surgical procedure that reshapes the uterus by removing the tissue that causes the heart-shaped appearance. But surgery usually isn't necessary — it's typically only for people with repeat miscarriages or a history of pregnancy complications.
Is a double uterus the same as a bicornuate uterus?
No, they're different. Uterus didelphys is when you're born with two uteruses (a double uterus).
When should I contact my provider if I have a bicornuate uterus?
If you experience pelvic pain during your period or during sex — and if you're pregnant, contact your provider immediately at any sign of labor, like contractions or your water breaking.
Related Reading
Preterm Labor: Recognizing Early Signs and Seeking Care: a key pregnancy risk with a bicornuate uterus, and the warning signs to know.
Endometriosis: Symptoms, Causes, and Treatment: a condition that is more likely when the uterus is irregularly shaped.
Hysterosalpingogram (HSG): Timing, What to Expect and What It Finds explains how an HSG checks the fallopian tubes and uterus.
References
Cleveland Clinic. Bicornuate Uterus. Cleveland Clinic. Updated August 27, 2025. https://my.clevelandclinic.org/health/diseases/22798-bicornuate-uterus
Kaur P, et al. Bicornuate Uterus. StatPearls. Updated July 6, 2025. https://www.ncbi.nlm.nih.gov/books/NBK560859/
Chan YY, et al. Reproductive outcomes in women with congenital uterine anomalies: a systematic review. Ultrasound Obstet Gynecol. 2011;38(4):371-82. PMID 21830244. https://doi.org/10.1002/uog.10056
Caballero Campo M, et al. Impact of congenital uterine anomalies on obstetric and perinatal outcomes: systematic review and meta-analysis. Facts Views Vis Obgyn. 2024;16(1):9-22. PMID 38551471. https://doi.org/10.52054/FVVO.16.1.004
Fedele F, et al. Assisted reproductive technology outcomes in women with congenital uterine anomalies: a systematic review. Arch Gynecol Obstet. 2024;310(5):2315-2332. PMID 39227392. https://doi.org/10.1007/s00404-024-07666-0
Medical disclaimer
The information in this article is for general informational purposes only and is not intended as professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here.
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