Incompetent Cervix: Overview

Definition of incompetent cervix (IC) or cervical insufficiency (CI): According to the University of Chicago Medical Hospital, “a woman’s cervix should open with the beginning of labor after about nine months of pregnancy. But in some women, pressure from a growing fetus in the uterus causes the cervix to open prematurely, leading to a second trimester pregnancy loss of what would otherwise be a normal full term delivery.”

While cervical insufficiency occurs in only one out of 100 pregnancies, the condition is responsible for approximately 25 percent of losses in the second trimester.

Risk factors:

  • You’ve had a previous loss in the second trimester that had no identifiable cause, or an early spontaneous preterm delivery that was not caused by preterm labor or a placental abruption. Your risk increases if you’ve had more than one late loss or early spontaneous preterm birth.
  • Your cervix was injured during a previous birth or dilation and curettage (D&C), or you’ve had several pregnancies terminated.
  • You’ve had a cone biopsy or LEEP (Loop Electrosurgical Excision Procedure). These are generally done to treat cervical dysplasia, a precancerous change in the skin on the cervix.
  • Your mother took the drug DES while she was pregnant with you.
  • Cervical insufficiency can also be genetic. Research shows an abnormal matrix metabolism can increase the risk of cervical incompetence. There are also multiple gene mutations associated with cervical incompetence, including mutations in COL1A1 and TGFB1, which may cause inflammation and the connective tissue metabolism malfunction found in IC.


Although cervical insufficiency is painless and often not discovered until it becomes an issue in a pregnancy, contact your doctor if you’re experiencing one or more of these symptoms:

  • Short cervix and/or funneling on ultrasound (<2.5cm)
  • Contractions
  • Crampiness
  • Increased discharge (mucus and/or blood)
  • Back pain