What Is an Isthmocele and How Can It Affect Fertility?

What Is an Isthmocele?

An isthmocele (also called a C-section scar defect or niche) is a pouch-like defect or thinning in the lower uterine wall at the site of a prior cesarean section incision.

  1. It’s essentially a small pocket or indentation where the uterus didn’t fully heal after a C-section.
  2. It’s usually located in the lower uterine segment, near the cervix.

Why Is It Important?

Many women with an isthmocele have no symptoms, but for some, it can cause:

  1. Abnormal bleeding after your period ends (“postmenstrual spotting”)
  2. Pelvic pain or cramping
  3. And in some cases: secondary infertility

How Can an Isthmocele Cause Infertility?

If you had a successful pregnancy before, but are now having trouble conceiving (called secondary infertility), an isthmocele may play a role by:

 

Issue

Impact

Fluid accumulation in the scar pouch

This fluid can leak into the uterus and interfere with embryo implantation

Inflammation or altered blood flow

Creates a less receptive environment for an embryo

Trapped menstrual blood

May disrupt the normal uterine lining or lead to chronic inflammation

Impaired sperm transport

In rare cases, the altered anatomy can affect sperm movement through the uterus

 

How Is It Diagnosed?

Your provider may suspect an isthmocele if you have:

  1. Secondary infertility
  2. Postmenstrual spotting
  3. A history of C-section

We typically confirm with:

  1. Transvaginal ultrasound with saline infusion (SIS) or
  2. Sonohysterogram
  3. Sometimes MRI or hysteroscopy if more detail is needed

How Is It Treated?

Treatment depends on your symptoms and fertility goals:

  1. Hysteroscopic surgery (minimally invasive)
  2. Removes scar tissue and reshapes the uterine wall
  3. Can improve implantation rates
  4. Laparoscopic repair
  5. Used for larger or deeper defects
  6. Monitoring only
  7. If you’re not symptomatic or already pregnant, no action may be needed

Takeaway

An isthmocele is a treatable cause of secondary infertility. If you’ve had a C-section and are now struggling to conceive or experiencing unusual bleeding, it’s worth exploring this possibility with your fertility provider.

Early diagnosis and appropriate treatment can improve your chances of a successful pregnancy.