Isthmocele (Cesarean Scar Defect): Symptoms, Diagnosis & Its Impact on Fertility

Introduction

All women experience physical changes during pregnancy and childbirth; however, many of these changes do not become readily visible after delivery. One change that should be noted during recovery is called isthmocele. An isthmocele is a pocket of tissue that may develop inside the uterine wall after a C-section (also known as a caesarean section) has taken place. Many women do not consider how the size of the C-section scar may have long-term effects on them. An isthmocele may lead to chronic pain in the pelvic area and may also prevent any future pregnancies from occurring.

What is an Isthmocele (Cesarean Scar Defect)?

An Isthmocele or Cesarean Scar Defect is a scar that occurs in the lower portion of the uterus (the area of the uterus affected by the C-section incision healing). During the actual C-section delivery, the surgeon will cut through both the abdominal wall and the muscle of the uterus. Ideally, the uterine laceration will heal to form a smooth, thick tissue layer. Still, in some instances, the tissue will heal inward, creating a small opening that forms a scar where fluid and blood collect over time, and the space widens, causing severe pain and bleeding.

Symptoms of Isthmocele

Although isthmocele does not have many apparent symptoms, the most predictable symptom is spotting (remnants of menstruation) of brown-colored blood a few days after the end of the normal menstrual cycle. Other symptoms of isthmocele could include:

• Fresh blood during sexual relations or during non-menstrual cycles
• The presence of cramps that are new or getting worse over time
• A feeling of fullness or pressure in the pelvis
• Pain or discomfort during sexual relations
• An unusual vaginal discharge unrelated to an infection

If you're trying to become pregnant, an isthmocele may impede sperm motility, create barriers for embryos to implant, and cause inflammation that makes implantation impossible. If you experience recurrent miscarriages or infertility following a normal and healthy pregnancy, a hidden pocket may indicate a scar from the isthmocele.

How is fertility affected by an isthmocele?

One of the most concerning features of isthmocele is its link to infertility. An undiagnosed isthmocele can negatively affect a woman's fertility, as discussed below:

• The most significant effect of isthmocele is that it collects old blood and mucus, which creates an environment that is not conducive to proper sperm migration to the egg. As a result, sperm may not be able to migrate properly, making it less likely for fertilisation to occur.
• Following fertilisation, the embryo relies on a healthy and viable uterine lining to implant and develop. However, with an isthmocele, the tissues of the uterus are scarred and inflamed, which negatively impacts the endometrial environment throughout the uterine lining. Therefore, correct implantation will be much more challenging for the embryo.
• An isthmocele may also increase the likelihood of early pregnancy loss, even when the embryo successfully implants. Miscarriage may result from inadequate blood supply to the poorly formed scar tissue or the inability of the embryo to attach securely to the uterine lining.

How is pregnancy affected by an isthmocele?

Pregnancy with an isthmocele presents several associated risks:

• Ectopic pregnancy: Any time an embryo implants itself outside the uterus, there will be an increased risk of ectopic pregnancy because of the abnormal uterine scar that results from the isthmocele.
• Placental abnormalities: If the placenta partially or fully covers the cervix, this is referred to as placenta previa; if the placenta has adhered to, or grown into, the uterine wall, this is known as placenta accreta. Both of these abnormalities are often seen in women with isthmocele and can lead to extreme bleeding during pregnancy and childbirth, along with significant discomfort.
• Uterine rupture: Although the risk of permanent uterine rupture is low during both prenatal and labour periods. If a woman has previously had one or more caesarean sections, or if the woman has a huge, fibrotic uterine scar, her risk for experiencing a uterine rupture is increased.

Diagnosis of Isthmocele

Doctors can use different methods to diagnose an isthmocele. These include the following:

• Transvaginal ultrasound: The first test that doctors would recommend is a transvaginal ultrasound. This allows doctors to visualise the uterine scar and identify any defects.
• Saline infusion sonohysterography: It may sometimes be recommended to obtain clearer images.
• Hysteroscopy: Hysteroscopy involves inserting a small camera through the cervix into the uterus so that the doctor can see the defect directly and assess the size and depth of the defect.
• MRI evaluation: It is generally used for complex cases or when results from other tests are unclear. An MRI provides a more detailed picture of the issues that need correcting.

Treatment Options for Isthmocele

• Treatment options for isthmocele range from conservative therapies to surgical interventions, depending on the diagnosis of isthmocele and the severity of symptoms.
• Conservative therapy is recommended for those with mild forms of isthmocele, where women have no severe pain or fertility problems associated with the condition. This typically includes hormone therapy that regulates abnormal menstrual flow and reduces complications of isthmocele.
• Surgical therapy is recommended for women with moderate or severe symptoms. There are several surgical techniques available, including robotic surgery, hysteroscopy, and laparoscopy, that can be used based on the complexity of the case. The primary goals of surgery are to repair the defect and to restore the normal anatomy of the uterus.

Conclusion

Isthmocele is a caesarean scar defect in case of C-section. It is an invisible condition that can have significant adverse effects on a woman's reproductive health once she has had a Caesarean section. Knowledge and awareness of isthmocele will help you understand the cause and treatment of this condition. Whether it is for health problems associated with a C-section or just to create a family, with the right healthcare provider, advanced treatment methods can successfully repair the isthmocele and restore the function of the uterus.