Cervical cerclages are often used in women who have an incompetent cervix, a cervix that is not able to stay closed during pregnancy. Cerclages have been used since the 1950s in women who are at risk for a preterm delivery, usually because they have had one or more second trimester miscarriages or very preterm births.
As ultrasound technology has improved, doctors have started placing cerclages after a cervical ultrasound shows that a woman’s cervix is beginning to dilate early in her pregnancy.
If a doctor determines that a cerclage is needed, it will usually be placed early in the second trimester of pregnancy. The risks of the procedure are about 1% and include:
- Premature rupture of membranes
Studies show that cerclage is most effective in women who are pregnant with only one baby and who have had 3 or more second trimester pregnancy losses or preterm deliveries. Cerclage is also effective in women with high-risk pregnancies where an ultrasound has shown that the cervix is beginning to dilate.
Cerclage is not often used in women who are pregnant with multiples, as research shows that cerclage may actually increase the risk of preterm birth in these women.
Morgan, Maria PhD, Goldenberg, Robert MD and Schulkin, Jay PhD. “Obstetrician-Gynecologists’ Screening and Management of Preterm Birth.” Obstetrics and Gynecology July 2008; 112, 35-41.
Fox, Nathan MD and Chervenak, Frank MD. “Cervical Cerclage: A Review of the Evidence.” Obstetrical and Gynecological Survey 63; 58-66.