The cervix (opening of the uterus) normally stays tightly closed during pregnancy. A
closed cervix helps the developing baby remain inside the uterus until it is ready to
be born. Occasionally, the cervix starts to open early, leading to miscarriage or
delivery of a baby that is too premature to survive. A cervical stitch (cerclage) is
used to prevent this early changes in a woman’s cervix, thus preventing mid
pregnancy fetal losses and preterm labour.
Cervical incompetence is a poorly defined but recognised cause of second and
early third trimester pregnancy losses.
There is uncertainty about any benefits of cervical cerclage, it should be
performed only in high-risk cases in which there is a cervical factor during the
second and third trimester of pregnancy.
The benefit of cervical cerclage for women who are found by ultrasonography
to have a short cervix remains uncertain since the numbers of randomized
women in available trials were too small to draw firm conclusions.