During pregnancy, as the baby grows and gets heavier, it presses on the cervix. This pressure
may cause the cervix to start to open before the baby is ready to be born. This condition is called incompetent
cervix or weakened cervix, and it may lead to a miscarriage or premature delivery. However, an incompetent cervix
happens in only about 1 out of 100 pregnancies.
What causes an incompetent or weakened cervix?
A weakened cervix can be caused by one or more of the following conditions:
Previous surgery on the cervix
Damage during a difficult birth
Malformed cervix or uterus from a birth defect
Previous trauma to the cervix, such as a D&C (dilation and curettage) from a termination or a
DES (Diethylstilbestrol) exposure
How will I know if I have an incompetent cervix?
Incompetent cervix is not routinely checked for during pregnancy and therefore is not usually
diagnosed until after a second or third trimester miscarriage has occurred.
Women can be evaluated before pregnancy, or in early pregnancy by ultrasound, if they have any
of the factors that are potential causes of incompetent cervix. Diagnosis can be made by your physician though a
pelvic exam or by an ultrasound. The ultrasound would be used to measure the cervical opening or the length of the
How often does an incompetent cervix happen?
An incompetent or weakened cervix happens in about 1-2% of pregnancies. Almost 25% of babies
miscarried in the second trimester are due to incompetent cervix.
What is the treatment for a weakened cervix?
The treatment for an incompetent or weakened cervix is a procedure that sews the cervix closed
to reinforce the weak cervix. This procedure is called a cerclage and is usually performed between week 14-16 of
pregnancy. These sutures will be removed between 36-38 weeks to prevent any problems when you go into labor.
Removal of the cerclage does not result in spontaneous delivery of the baby. A woman would not be eligible for a
Possible complications of cervical cerclage include uterine rupture, maternal hemorrhage,
bladder rupture, cervical laceration, preterm labor and premature rupture of the membranes. The likelihood of these
risks is very minimal, and most health care providers feel that a cerclage is a life saving procedure that is worth
the possible risks involved.