Isthmocele (Cesarean Scar Defect)

An isthmocele (also called a cesarean scar defect or niche) is a small pouch or dent of scar tissue that can form in the front wall of your uterus after a C-section. It develops when your C-section incision doesn’t heal completely.

They can range in severity — from mild indents that cause no symptoms to deeper defects that weaken your uterine wall and cause pain. Symptoms can include bleeding between periods and pelvic pain. The most common treatment is surgery to remove excess scar tissue. You can have healthy pregnancies after treatment.

Studies suggest that about 2 to 7 out of 10 women who’ve had at least one C-section develop some degree of isthmocele.

Symptoms of an isthmocele

You may not have symptoms for months or years after a C-section. Many women don’t know they have a C-section scar defect until they can’t get pregnant.

Symptoms can include:

• Irregular periods or bleeding between periods
• Difficulty getting pregnant
• Painful periods
• Pain during sex
• Pelvic pain

Isthmocele causes

A C-section involves two incisions: One in your abdomen and one in your uterus. If the incision in your uterus doesn’t heal completely or you’ve had multiple incisions in the same area, the tissue around it becomes thin. It can form a pouch that fills with fluid and blood.

Risk factors

Anyone who has a C-section can develop a cesarean scar defect.

The location of your incision can affect your risk, too. Cuts made very low on your uterus tend to leave larger scars, especially if you were in labor before surgery. Using one layer of stitches instead of two to close the incision can also raise your risk.

Your risk of isthmocele is also higher if you have:

• Overweight/obesity before and during your pregnancy
• A medical condition that prevents wound healing
• An unplanned C-section late in labor
• Diabetes or gestational diabetes
• Had multiple C-sections

If you’re pregnant and planning a C-section, talk to your healthcare provider about the risks.

Complications of C-section scar defect

When left untreated, complications can include:

• Increased risk of complications, like uterine rupture
• Placental problems in your next pregnancy
• Ectopic pregnancy
• Secondary infertility

Can it cause an infection?

Yes. The pouch of scar tissue can trap blood or fluid. This creates a place for bacteria to grow, which can lead to infection.

How doctors diagnose isthmoceles

Imaging tests can diagnose isthmoceles. The best time to perform imaging is right after your period when the niche is likely full of blood. This makes it easier to see in images.

Your healthcare provider may perform:

• Transvaginal ultrasound: Your healthcare provider inserts an ultrasound wand into your vagina. The defect may show up as a darker area. This is usually the first test your provider does.
• Sonohysterogram: Your provider fills your uterus with saline before doing a transvaginal ultrasound. The water fills the niche, making it easier to see its size and depth.
• Hysteroscopy: Your provider inserts a thin camera through your cervix into your uterus. It can most clearly detect the size and depth and how it may be causing problems. This step usually happens when surgical treatment is necessary.

How is it treated?

There are several treatments for isthmoceles. Not everyone needs treatment, though. It depends on your symptoms, the size of the defect and future pregnancy plans.

Possible treatment options are:

• Hysteroscopic repair: During a hysteroscopy, your healthcare provider removes uterine scar tissue through your vagina. They also open the sides of the niche to let blood and fluid drain out. It doesn’t require incisions in your belly.
• Laparoscopic repair: Your healthcare provider makes one or more small cuts in your belly. They insert a thin, lighted tube (laparoscope) to see the inside of your uterus. With other tools, they remove scar tissue and extra tissue around the niche.
• Hormone medications: Birth control and other medications can regulate your periods and lighten menstrual blood flow. This can help with irregular bleeding, but it won’t fix the defect.
• Hysterectomy: Removing your entire uterus is rarely necessary. But if your defect is large, you have severe symptoms and don’t want another pregnancy, your provider may suggest it.

Can isthmocele go away?

No, it doesn’t go away on its own. But you don’t always need treatment either.

When should I see my healthcare provider?

Contact your provider if you notice any of these symptoms after a C-section:

• Spotting between periods
• Difficulty getting pregnant
• Pelvic pain or pain during sex
• Signs of infection, like fever or foul-smelling vaginal discharge

Seek medical attention right away if you experience severe pelvic pain, pain on your C-section scar or heavy vaginal bleeding. These could be signs of a ruptured uterus.

What can I expect if I have an isthmocele?

Everyone’s experience with the condition is different. Some women have a small pouch for the rest of their lives with no problems. Others may have pain or difficulty getting pregnant. The positive news is that there are treatments available to help you. Many women find relief from their symptoms while keeping their ability to get pregnant. Talk to your provider about your wishes so they can recommend the best treatment for you.