An incompetent cervix is a condition that causes the opening of the lower part of the uterus (cervix) to open (dilate) too early during pregnancy. This happens before the pregnancy reaches full term and before labor begins.
Normally, the cervix stays tightly closed as the weight of the baby and the contents of the uterus increase. If the cervix is incompetent, the weight of the fetus and amniotic fluid cause it to open (dilate) too early, which may cause preterm labor.
An incompetent cervix may result from:
Cerclage, a procedure in which the cervix is sewn shut, has been known to allow pregnancy to continue until it is safe for the baby to be born. But it is rarely done because it is hard to know which women will benefit from the procedure. In rare cases, cerclage can cause infection.
WebMD Medical Reference from Healthwise