SUPERStudy: Cervical Incompetence (Cervical Insufficiency)

Introduction:
Cervical incompetence refers to the inability of the cervix to maintain a pregnancy due to painless cervical dilatation in the absence of uterine contractions, leading to pregnancy loss or preterm birth, typically in the second trimester.

Epidemiology: About three-fourths of spontaneous pregnancy losses (spontaneous abortions) occur before the 16th week

Key Points:

1.Etiology:

• • Congenital factors: Collagen abnormalities (e.g., Marfan syndrome, Ehlers-Danlos syndrome), uterine anomalies, abnormal cervical development, including that from diethylstilbestrol (DES)
  • Acquired factors: Trauma from previous cervical surgeries (e.g., loop electrosurgical excision procedure [LEEP], cone biopsy), dilation and curettage, or obstetric injury infections, dietary deficiencies, diabetes mellitus, hypothyroidism, antiphospholipid antibody syndrome.
  • More than 60% of spontaneous losses result from chromosomal defects due to maternal or paternal factors; about 15% appear to be associated with maternal trauma, infections, dietary deficiencies, diabetes mellitus, hypothyroidism, antiphospholipid antibody syndrome, or anatomic malformations. 

2.Clinical Presentation:

• • Painless cervical dilatation in the second trimester.
  • History of recurrent second-trimester pregnancy losses or preterm births without labor symptoms.

3.Diagnosis:

• • Before pregnancy or during the first trimester, there are no methods for determining whether the cervix will eventually be incompetent. After 14–16 weeks, ultrasound may be used to evaluate the internal anatomy of the lower uterine segment and cervix for the funneling and shortening abnormalities consistent with cervical incompetence.
  • Ultrasound findings: Shortened cervical length (<25 mm before 24 weeks of gestation), funneling, or effacement.
  • History-based diagnosis in women with characteristic obstetric history.

4.Management:

• • Cervical cerclage:A cerclage is the treatment of choice for incompetent cervix, but a viable intrauterine pregnancy should be confirmed before placement of the cerclage.

Bleeding, rupture of the membranes, contractions and infection are specific contraindications to cerclage. Testing for N gonorrhoeae, C trachomatis, and group B streptococci should be obtained before elective placement of a cerclage. N gonorrhoeae and C trachomatis should betreated before placement. Patients should consider abstaining from sexual intercourse.

• • Prophylactic cerclage: For women with a history of cervical insufficiency, placed at 12-14 weeks.
  • Rescue cerclage: Placed after cervical changes are detected, if no active labor or infection is present.
• Progesterone supplementation: Vaginal progesterone may be used in women with a short cervix.
• Lifestyle modifications: Activity modification and avoidance of prolonged standing or heavy lifting.

5.Prognosis:

• • Early identification and intervention improve pregnancy outcomes.
  • Success rates depend on the timing of intervention and the degree of cervical insufficiency.

Note: Counseling on future pregnancies and individualized care is crucial for optimizing outcomes.

SUPERFormula: Cervical incompetence 

SUPERPoint 

References: 

Current Medical Diagnosis & Treatment 2025

Maxine A. Papadakis, Michael W. Rabow, Kenneth R. McQuaid, Monica Gandhi

Williams Obstetrics, 26e

F.Gary Cunningham, Kenneth J. Leveno, Jodi S. Dashe, Barbara L. Hoffman, Catherine Y. Spong, Brian M. Casey