Diagnosing and Treating Cervical Incompetence

​Cervical incompetence, also known as cervical insufficiency, is a condition affecting the cervix, the uterus’ lower portion that opens into the vagina. Prior to pregnancy, the cervix is usually firm and closed at the lower end. During the earlier stages of pregnancy, it remains closed, only thinning, shortening (effacing), softening, and dilating (opening) as childbirth approaches. When cervical thinning, shortening, or softening occurs too early, miscarriage and premature birth can result. The fetus is born before the organs have fully developed and cannot easily survive outside the womb.

A fibromuscular organ, the cervix goes through extensive changes during gestation and childbirth. As gestation progresses, the maternal cervix is transformed through timed biochemical cascades, extracellular and cellular interactions, and infiltration by inflammatory cells within the cervical stroma. The latter is a dense, fibrous tissue that allows the passage of lymphatic, vascular, and nerve supplies to and from the cervix. When any of these processes is disrupted, preterm birth or miscarriage may occur.

Incompetent cervix is implicated in approximately one in 100 pregnancies. While cervical incompetence can be an issue for anyone, women at higher risk tend to have a uterus or cervix that is irregularly shaped. They may have previously had a miscarriage or premature birth or suffered an injury to the uterus or cervix during past childbirth or pregnancy. Surgery on the cervix also increases risks, as does Ehlers-Danlos syndrome and other genetic disorders that weaken the cervix. Women expecting twins and triplets, as well as African Americans, also have a higher chance of developing the condition.

Physicians generally identify cervical insufficiency in the second or early third trimester. Unfortunately, such diagnosis is often retrospective: In many cases, preterm premature rupture of membranes (PPROM) has already occurred due to progressive cervical dilation, resulting in spontaneous preterm birth or mid-trimester pregnancy loss.

Diagnosis often starts with a finding of “painless dilation without labor” through a physical exam. Ultrasound can identify a shortened cervix (less than 25 millimeters long, with less than 24 weeks gestation). Women with a prior history of preterm births and second-trimester losses are closely monitored as well.

The most common treatments are vaginal progesterone and cervical cerclage. Taken as a tablet (Endometrin) or applied as a gel (Crinone), vaginal progesterone is among a medication class known as progestins, which impact female hormones. Its varied uses include fertility treatment and assisted reproductive technology, as it boosts embryo implantation rates and decreases miscarriage risks. Vaginal progesterone also helps bring on menstruation and reduces preterm birth rates among women with short cervix, regardless of preterm birth history.

Performed in the second trimester, cervical cerclage involves the physician using stitches to temporarily sew the cervix closed during pregnancy. There are two basic types of cerclage.

With transvaginal cerclage, the ob-gyn reaches through the vagina to place stitches in the cervix. Transabdominal cerclage involves an incision and is recommended for women who have had previous cervical surgeries or previous transvaginal cerclage that didn’t prevent pregnancy loss. It requires a cut in the abdomen as a way of accessing the cervix and placing stitches. The cut may involve either traditional laparotomy (open surgery) or minimally invasive laparoscopy, pairing an extremely small cut with a tiny inserted camera.

Alex Culbreth GA

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