An "incompetent" cervix is a weakened cervix that predisposes a woman to mid-term miscarriage or early (premature) delivery.
The cervix is the narrow point at the base of the uterus (fig. 1). In a healthy pregnancy, the cervix dilates or opens near the very end of the term, before labor begins. When the cervix has been weakened, it may open too early in the pregnancy, threatening miscarriage or early (premature) delivery.
Miscarriages that result from an incompetent cervix generally occur four months into the pregnancy or later. This is when the fetus and amniotic fluid weigh enough to cause the weakened cervix to dilate. About 25% of miscarriages that occur after the 14th week of pregnancy are attributed to cervical incompetence.
The exact cause of an incompetent or weakened cervix is unknown, though it is sometimes associated with a previous traumatic birth (during which the cervix was torn), a cone biopsy, or repeated or late-term abortion. It is also associated with an abnormally developed cervix, a finding in daughters of mothers who were exposed to the drug DES (diethylstilbestrol) during their pregnancy.
How Do I Know I Have It?
If you have a history of miscarriages in the second trimester or other indicators of an incompetent cervix (such as being a "DES" daughter), talk to your doctor about your cervical health.
Generally, there are no symptoms of an incompetent cervix; so few women realize they have the condition until they miscarry. Symptoms of a miscarriage due to an incompetent cervix include abdominal pressure and feeling a "lump" in the vagina.
If your doctor suspects an incompetent cervix, he or she may suggest an ultrasound to examine the thickness of your cervical tissue. The ultrasound may be performed when you are planning a pregnancy or are in the early stages of a pregnancy.
How Can I Treat It?
Cerclage (fig. 1), a surgical procedure, successfully treats incompetent cervix 85% to 90% of the time. This procedure is usually done under spinal or epidural anesthesia and involves stitching the cervix closed with a strong thread for the full-term of the pregnancy. After having cerclage, a woman is usually prescribed medication to prevent a surgery-related miscarriage. The stitches are removed around the ninth month of pregnancy, or sooner if labor commences, to prepare for delivery.
Frequently Asked Questions
Q: Will I have to worry about cervical incompetence in my next pregnancy?
A: Yes. Generally, a woman who has this condition will need to take precautions in subsequent pregnancies.
Review Date: June 29, 2001
Reviewed By: Peter Chen, M.D., Obstetrics and Gynecology, University of
Pennsylvania School of Medicine. Review provided by VeriMed Healthcare
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