A double uterus is a rare condition that is present at birth in some women. In a female fetus, the uterus starts out as two small tubes. As the fetus grows, the tubes typically join to create one larger, hollow organ. This organ is the uterus.

Sometimes the tubes don't join completely. Instead, each one develops into a separate organ. A double uterus may have one opening into one vagina. This opening is called the cervix. In other cases, each uterus has its own cervix. Often, there's also a thin wall of tissue that runs down the length of the vagina. This divides the vagina in two, with two separate openings.

Women who have a double uterus often have successful pregnancies. But the condition can make you more likely to have a miscarriage or premature birth.

A double uterus often causes no symptoms. The condition may be discovered during a regular pelvic exam. Or it may be found during imaging tests to find the cause of repeated miscarriages.

Women who have a double vagina along with a double uterus may first see a health care provider for menstrual bleeding that isn't stopped by a tampon. This can happen when a tampon is placed in one vagina, but blood still flows from the second uterus and vagina.

When to see a doctor

Seek medical advice if you have a menstrual flow despite using a tampon. Or if you have severe pain during your periods or you have repeated miscarriages.

Health experts don't know exactly why some fetuses develop a double uterus. Genetics may play a role. That's because this rare condition sometimes runs in families.

The risk factors for a double uterus are not well understood. The cause of the condition isn't known either. Genetics likely plays a role, along with other unknown factors.

Many women with a double uterus have active sex lives. They also may have routine pregnancies and successful deliveries. But sometimes a double uterus and other uterine factors can cause:

• Infertility.
• Miscarriage.
• Premature birth.
• Kidney problems.

A double uterus may be diagnosed during a routine pelvic exam. Your doctor may observe a double cervix or feel an unusually shaped uterus. To confirm the diagnosis of double uterus, you may need certain tests:

• Ultrasound. This test uses high-frequency sound waves to create images of the inside of your body. To capture the images, a device called a transducer is pressed against the outside of your lower belly. Or you may have the transducer put into your vagina. This is called transvaginal ultrasound. You may need both types of ultrasound to get the best view. A 3D ultrasound may be used, if it's available at your facility.
• Sonohysterogram. The sonohysterogram (son-o-HIS-ter-o-gram) is a special type of ultrasound scan. You have fluid injected through a tube into your uterus. The fluid outlines the shape of your uterus on the ultrasound scan. This allows your doctor to look for anything unusual.
• Magnetic resonance imaging (MRI). The MRI machine looks like a tunnel that has both ends open. You lie down on a movable table that slides into the opening of the tunnel. This painless test uses a magnetic field and radio waves to create cross-sectional images of the inside of your body.
• Hysterosalpingography. During a hysterosalpingography (his-tur-o-sal-ping-GOG-ruh-fe), a special dye is injected into your uterus through your cervix. As the dye moves through your reproductive organs, X-rays are taken. These images show the shape and size of your uterus. They also show if your fallopian tubes are open.

Sometimes, ultrasound or MRI is also done to check for kidney problems.

Treatment often isn't needed for a double uterus if you have no symptoms or other problems. Surgery to join a double uterus isn't usually done.

But sometimes surgery can help. If the uterus is partially divided, and you've had a pregnancy loss with no other medical explanation for the loss, your doctor might recommend surgery. This may help you keep a future pregnancy.

Surgery also might help if you have a double vagina along with a double uterus. The procedure removes the wall of tissue separating the two vaginas. This can make childbirth a little easier.

You may start by seeing your primary doctor or other care provider. Or you may be referred to a specialist. This could include seeing a doctor, called a gynecologist, who specializes in conditions that affect the female reproductive system. Or you may see a doctor who specializes in reproductive hormones and helping with fertility. This type of doctor is called a reproductive endocrinologist.

What you can do

When you make the appointment, ask if there's anything you need to do to get ready. You may be given instructions for preparing for certain tests. Next, make a list of:

• Your symptoms, including any that seem unrelated to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins or other supplements you take, including the doses. The dose is how much you take.
• Questions to ask your doctor.

Bring a family member or friend along, if you're able to. They can help you remember what you talk with your doctor about during your appointment.

For a double uterus, some basic questions to ask your doctor include:

• What's likely causing my symptoms?
• Could there be other possible causes for my symptoms?
• Do I need any tests done?
• Do I need treatment?
• Are there any alternatives to the treatment you're suggesting?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Do you have any brochures or other printed material I can take with me? What websites do you recommend?

Don't hesitate to ask other questions as they occur to you.

What to expect from your doctor

Your doctor may ask you several questions, such as:

• When did your symptoms begin?
• Do your symptoms happen all the time or only every so often?
• How bad are your symptoms?
• Do you have regular periods?
• Have you ever been pregnant?
• Have you ever given birth?
• Does anything seem to make your symptoms better?
• Does anything seem to make your symptoms worse?