As a pregnant woman’s body prepares for labor, late in the third trimester, the cervix – the long, tubular lower end of the uterus – begins to soften, shorten (efface), and open (dilate). In about one out of 100 pregnancies (approximately 1 percent), the pressure of the baby on the cervix may cause it to open too soon, a condition known as cervical incompetence or cervical insufficiency, which may result in miscarriage or preterm delivery.
Regrettably there is no reliable way to screen for an incompetent cervix before pregnancy, particularly with a first pregnancy. But based on a complete physical exam and history, medical professionals can identify women who are at risk and with appropriate treatment can reduce the chances of a preterm delivery.
What causes cervical incompetence? Who is at risk?
There are a couple of known causes for cervical incompetence. The cervix may be weakened by damage from a previous difficult delivery or gynecological procedure, or from a congenital defect. Women who have had one or more second-trimester miscarriages with no known cause, one or more spontaneous preterm deliveries, or a previous pregnancy with a diagnosed incompetent cervix are at risk.
Cervical incompetence might not have any symptoms or they might be mild, generally occurring between weeks 14 and 20, including changes in vaginal discharge, light bleeding, pelvic pressure, cramps or backache.
Management and Treatment
Women who are at risk for cervical incompetence are monitored carefully in the second trimester. With a combination of ultrasound and pelvic exam, it is possible to detect shortening or opening of the cervix and, if needed, take further steps to protect the pregnancy. The primary treatment if the cervix is opening is a procedure called cervical cerclage, which can help prevent premature birth. Cerclage closes the cervix with sutures that are removed during the last month of pregnancy or during labor. Women who have a diagnosed history of cervical incompetence may undergo a prophylactic cerclage before the cervix opens, usually around week 14. Cerclage is usually performed as an outpatient procedure.
If the cervix has been weakened, cervical incompetence cannot be prevented. But following the guidelines for a healthy pregnancy can help ensure a successful outcome. Most important is prenatal care, especially reporting full medical history and any symptoms to caregivers and following advice to limit physical activities, if necessary. Healthy habits are also critical. Women should eat a healthy diet, manage weight gain, and avoid alcohol, tobacco and illicit drugs. With good medical and self-care, cervical incompetence can be managed and treated and the pregnancy carried to full term.
Kecia Gaither, M.D., MPH, FACOG, a perinatal consultant and women’s health expert, is a double board-certified physician in OB/GYN and Maternal-Fetal Medicine. Gaither is Director of Perinatal Services at NYC Health+Hospitals/Lincoln. kecia