What Is Isthmocele?
An isthmocele is a defect formed in a cesarean scar. It is a defect in the anterior uterine wall, where the previous cesarean section scar is present. There is a discontinuity of the myometrium, which is the middle layer of the uterine wall. Depending on the wall thickness of this myometrial discontinuity, it is divided into a small or large defect.
This condition is usually asymptomatic. When symptoms do occur, abnormal vaginal bleeding and pelvic pain are the symptoms. Some of the complications of isthmocele are infertility, placenta praevia, uterine rupture, placenta accreta, ectopic pregnancy, and scar dehiscence.
Women who undergo multiple cesarean sections are at risk of developing this condition. There are no definitive criteria for diagnosing this condition, and your doctor might take several images to visualize your uterus and its walls.
Your doctor will decide the treatment based on the size of the defect and associated symptoms. The treatment option includes clinical or surgical management. Read the article to know more about this condition in detail.
What Are the Types of Isthmocele?
An isthmocele is divided based on the size of the defect. The types are:
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Large Defect - the thickness of the myometrium left is less than 2.5 to 3.0 mm.
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Small Defect - the thickness of the myometrium left is more than 3.0 mm.
They can also be classified as:
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Symptomatic Isthmocele - the patient might experience abnormal vaginal bleeding and pelvic pain.
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Asymptomatic Isthmocele - here, the patient does not show any symptoms.
What Are the Signs and Symptoms of Isthmocele?
Most women with isthmocele are asymptomatic, and they might consult different physicians before this diagnosis is made. If the woman does experience symptoms, then the most frequent ones are:
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Intermittent postmenstrual bleeding - The defect acts as a reservoir, where the blood during menstruation gets collected. Around 28.9 % to 30 % of women with isthmocele experience abnormal vaginal bleeding. Women with a large defect are reported to have complained about abnormal uterine bleeding more frequently.
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Abdominal cramps and pelvic pain - As the uterus tries to contract and empty the contents of the isthmocele. And the defect can also cause irregular uterine contractions.
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Dysmenorrhea (painful menstruation).
As these symptoms are seen in almost all other common gynecological problems, this condition is usually overlooked.
What Causes Isthmocele?
The exact mechanism behind the formation of an isthmocele is not understood completely. But, several risk factors have been identified that increases the risk:
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Multiple previous cesarean sections.
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Retroflexed uterus (the uterus curves in a backward position at the cervix).
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C-section that was done in active labor with cervical dilatation of more than 5 cm is associated with a larger isthmocele.
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A single-layer closure of the myometrium also increases the risk.
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Genetic predisposition to impaired wound healing and poor hemostasis.
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A lower cesarean section.
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Early adhesions of the uterine wall.
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Incomplete closure of the hysterotomy.
How Is an Isthmocele Diagnosed?
As mentioned before, no definitive diagnostic criteria are available for isthmocele. The doctor will use imaging methods such as ultrasonography, hysterography, sonohysterography, MRI (magnetic resonance imaging), and hysteroscopy, and to visualize the anterior wall of the uterus.
The gynecologist will initially perform a TVUS (transvaginal ultrasound) to assess the integrity of the uterine wall in women who are not pregnant. This test might show the collection of menstrual blood in the uterine wall defect. Both TVUS and saline infusion sonohysterography (SIS) are sensitive and cost-effective methods to diagnose this condition.
How Is an Isthmocele Treated?
There is no standard treatment available for an isthmocele. The doctor will suggest treatment only if you have symptoms. The treatment options include:
1) Medicines - Some doctors prescribe oral contraceptive pills to suppress menstruation, which is said to improve symptoms. But this treatment option is not suitable for women who are trying to conceive.
2) Intrauterine Device (IUD) - The other option to suppress menstruation is by getting a copper or hormonal IUD. This, again, is not feasible for women planning to get pregnant.
3) Surgery - Surgical options include:
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Hysteroscopic and Laparoscopic Resection and Repair of the Defect - It has been shown to be successful in treating infertility and abnormal bleeding. Surgery is usually carried out when the residual myometrium thickness is less than 3 mm. Such restorations help couples planning a pregnancy and help reduce the risk of uterine rupture. The risks associated with laparoscopic surgery are incomplete scar tissue removal or uterine and bladder perforation.
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Transvaginal Repair - Instead of repairing the isthmocele laparoscopically, the defect is repaired from inside the uterus.
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Hysterectomy - For large and symptomatic isthmocele, and if the woman does not wish to conceive anymore, the uterus is surgically removed.
What Are the Possible Complications of an Isthmocele?
The possible complications of isthmocele are:
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Infertility - Isthmoceles might cause infertility, as it can affect the sperm motility and implantation of the embryo.
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Cesarean Scar Ectopic Pregnancy - It also increases the risk of ectopic pregnancies. The fertilized egg gets implanted in the isthmocele. As the pregnancy progresses and the baby grows, the walls of the uterus might rupture. This can be fatal for both the mother and the fetus.
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Placenta Previa - When the placenta lies low on the uterus.
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Scar Dehiscence - The thin uterine wall can open up and result in uterine rupture.
Doctors usually suspect isthmocele when a woman with a history of a cesarean section presents with secondary infertility, pelvic pain, or abnormal bleeding. With the number of cesarean sections increasing, the number of cases of isthmocele is also going up. For more information, consult an obstetrician and gynecologist online.
