Before pregnancy, the cervix is closed and rigid. During pregnancy, the cervix gradually softens, decreases in length (effaces) and opens (dilates) in preparation for birth. If you have an incompetent or weak cervix, however, your cervix might begin to open too soon. As a result, you could experience pregnancy loss or give birth prematurely.

Your health care provider might recommend cervical cerclage during pregnancy to prevent premature birth if you have:

  • A history of one or more second trimester pregnancy losses related to painless cervical dilation and in the absence of labor or placental abruption (history-indicated cervical cerclage)
  • Prior cerclage due to painless cervical dilation in the second trimester
  • Upon physical exam, painless cervical dilation diagnosed during the second trimester
  • A singleton pregnancy, a prior spontaneous premature birth at less than 34 weeks, and, upon ultrasound exam, a short cervical length (less than 25 millimeters) before 24 weeks of gestation

Cervical cerclage isn't appropriate for everyone at risk of premature birth. Your health care provider might discourage cervical cerclage if you have:

  • Vaginal bleeding
  • Preterm labor
  • An intrauterine infection
  • Preterm premature rupture of membranes — when the fluid-filled membrane that surrounds and cushions the baby during pregnancy (amniotic sac) leaks or breaks before week 37 of pregnancy
  • A multiple pregnancy
  • A fetal anomaly incompatible with life
  • Prolapsed fetal membranes — a condition in which the amniotic sac protrudes through the opening of the cervix
March 17, 2015