Signs and Symptoms of Incompetent Cervix

Incompetent cervix is often asymptomatic. Some women do experience mild symptoms. Doctors should consider risk factors and monitor the pregnancy carefully. 

These signs of incompetent cervix typically appear between weeks 14 and 20 of pregnancy:

• Sensation of pelvic pressure
• Backache
• Abdominal cramps
• Change in vaginal discharge (volume, color, or consistency)
• Light vaginal bleeding/spotting
• Braxton-Hicks-like contractions

Incompetent cervix and cervical weakness have similar causes. (Cervical weakness is when the cervix is not strong enough to withstand the weight of the growing baby.) 

Previous childbirths, surgical procedures, and individual anatomy may lead to incompetent cervix. Physicians must take a thorough history of the pregnant parent to identify risk factors for an incompetent cervix and premature birth.

Risk factors for incompetent cervix include:

• Short cervical length
• Prior miscarriage
• Prior preterm delivery
• Prior D&C procedure
  • D&C, or dialation and curettage,is a procedure to clear the uterine lining after a miscarriage or pregnancy termination. It can also diagnose and treat certain uterine conditions
• Prior loop electrosurgical excision procedure
  • LEEP removes abnormal or potentially cancerous cells from the cervix
• History of other surgical procedures involving the cervix
• Diagnosis of incompetent cervix in a previous pregnancy
• Twins or multiples pregnancy
• Torn cervix from a previous childbirth(obstetric trauma)
• Repeated or late-term abortion
• Uterine abnormalities and anomalies
• Exposure to the drug diethylstilbestrol 
  • DES is a synthetic form of the hormone estrogen

The physician should review the pregnant parent’s history to check for risk factors of incompetent cervix. In addition, they should perform a physical exam and ultrasound tests to measure the length of the cervix. 

The diagnostic process typically involves taking:

• Patient History: Miscarriages or extremely premature births can be important indicators of an incompetent cervix. Physicians should ask about any surgeries or other procedures related to the cervix. 
• Physical exam: During the second or third trimester, a pelvic exam can reveal signs of incompetent cervix. Changes to the cervix like early dilation, shortening, and thinning of the cervix would indicate  a weak cervix.
• Tests: The physician should order serial transvaginal ultrasound studies (TVS) for anyone with risk factors for cervical incompetence. Transvaginal ultrasounds can help monitor the cervical length and determine if the cervix is shortening or opening.

There are two important treatments for incompetent cervix – cervical cerclage and progesterone.

A cervical cerclage is a type of surgery that can help reinforce cervical muscle and prevent premature birth. During cerclage, a strong suture is sewn in and around the cervix, which helps it remain closed under the weight of the baby.

According to the American College for Obstetricians and Gynecologists (ACOG), eligibility for cerclage can be based off of the following factors.

• A history of incompetent cervix
• Physical examination findings (advanced dilation of the cervix without pain, and no signs of placental abruption or intraamniotic infection)
• A history of premature birth combined with certain ultrasonographic findings

ACOG recommends that cerclages only be performed in the second trimester. A cerclage works best before the fetus is viable (able to live outside the womb). This means the surgery should generally occur prior to 24 weeks of gestation. Cerclage is extremely effective in prolonging pregnancy in the face of cervical insufficiency.

Medical staff should remove a cerclage around 36-37 weeks of pregnancy, before the onset of labor. In the case of premature labor or the water breaking, physicians may need to remove the cerclage earlier. 

Cerclage is not recommended in these circumstances: 

• preterm premature rupture of membranes (PPROM)
• placental abruption
• infection
• preterm labor.

Progesterone is a pregnancy hormone that helps to prevent premature contractions and birth. This hormone also benefits the growing baby in a variety of other ways.

Patients with incompetent cervix should benefit from progesterone treatment. It can reduce the risk of premature birth. In 2023, ACOG updated its recommendations for progesterone treatment. ACOG recommends only using progesterone for patients with a shortened cervix, a history of preterm birth, and a single gestation. 

In cases without a shortened cervix, vaginal progesterone is not proven effective at preventing preterm birth. Progesterone is not recommended for multiple pregnancies.

Premature babies are at higher risk of birth injuries and subsequent disabilities because of their underdeveloped organs and low birth weight. Conditions associated with premature birth include:

• hypoxic-ischemic encephalopathy (HIE)
• cerebral palsy (CP)
• intellectual and developmental disabilities (I/DDs)
• hearing and vision impairments

Doctors must do all they can to prevent premature birth. They should monitor for incompetent cervix in pregnancies and ensure prompt treatment to minimize the risk of premature birth or injury.