Womens Health

Incompetent Cervix: Late-Trimester Complications


Incompetent Cervix, also known as a weak cervix or cervical insufficiency, refers to a condition where a woman's cervix is weak and therefore dilates before it should during pregnancy. Normally the cervix remains closed until labor, holding the fetus and amniotic sac in place. In the case of an incompetent cervix, however, the baby grows and puts pressure on the cervix and the membranes of the amniotic sac holding the fetus stretch, weaken, and eventually break. This can lead to a miscarriage, stillbirth, or a premature delivery.

While approximately 80% of all pregnancy losses occur during the first trimester, some women suffer miscarriages in the second or third trimester. It is estimated that 20-25% (1 out of 100) of all second-trimester losses are caused by a weak or incompetent cervix.


Unfortunately, there are usually no warning signs or symptoms for this condition. An incompetent cervix dilates without any contractions, the water breaks, and the baby is born or lost. Thus until a second or third trimester miscarriage has occurred, the condition is usually not diagnosed.

However, if a pregnant woman has experienced second or third trimester losses, it is generally assumed that she has or is at risk for a weakened cervix and should be checked routinely.

Risk Factors

Women who have experienced the following conditions may be at risk for an incompetent cervix:

· Previous cervical surgeries or biopsies

· Previous damage from a difficult birth

· Previous cervical trauma, i.e., a D&C (dilation and curettage) or miscarriage

· Malformed cervix or uterus resulting from a birth defect

· Fetal exposure of the mother to Diethylstilbestrol (DES)

· Repeated late-term abortions

Diagnosis and Treatment

Fortunately, if cervical incompetence is detected early it is possible to prevent the loss of a baby. Diagnosis can be made by your doctor via a manual pelvic exam, which determines whether the cervix is dilating, or by an ultrasound, which measures the cervical opening and the length of the cervix.

If your cervix is dilating early, a procedure called cervical cercalge can be performed, wherein the cervix is stitched closed while the baby develops and is then removed later on to allow for a regular birth process. In conjunction with cerclage, medications are sometimes prescribed. These treatment measures have a high success rate of 85-90%, where women successful carry to term and give birth to healthy babies.

Rare complications associated with cervical cerclage include: Cervical laceration; rupture of the uterus or bladder; maternal hemorrhage; preterm labor; premature rupture of the membranes.

Future Pregnancies

After experiencing a complication due to a weak cervix, women should consult with a high-risk pregnancy specialist before conception and early on during pregnancy.

If you have suffered from cervical insufficiency, you are at risk for a re-occurrence of complications in your next pregnancies. Besides frequent prenatal checkups and careful monitoring of your cervix, your doctor may give you other special instructions, such as avoiding sexual intercourse or reducing strenuous exercise.

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