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:
- Damage to the cervix after a small section was
surgically removed for testing (cone biopsy) or a loop electrosurgical excision
procedure (LEEP).
- Surgical scraping of the inside of the uterus
(dilation and curettage, or D&C).
- Damage to the cervix from a
previous difficult birth.
- A birth defect of the mother that caused
her to have an abnormal cervix.
- Unknown reasons.
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.
However, it is rarely done because it is difficult to know which women will
benefit from the procedure. On rare occasions, cerclage can cause
infection.
