Management of Short Cervix in Pregnancy

Definition and Measurement

A cervical length ≤25 mm before 24 weeks of gestation is considered short in singleton gestations, as defined by the American College of Obstetricians and Gynecologists, with measurements performed using a transvaginal approach following standardized procedures 1
Cervical length measurements should follow standardized procedures as described by organizations such as the Perinatal Quality Foundation or the Fetal Medicine Foundation 1
Transvaginal ultrasound is the gold standard and reference method for cervical length assessment, with transperineal ultrasound as an acceptable alternative when transvaginal assessment is not possible 2, 1

Vaginal progesterone is the recommended first-line intervention for patients with a short cervix (≤25 mm) in singleton pregnancies without a history of spontaneous preterm birth, with specific management determined by the exact cervical length measurement (GRADE 1A evidence) 1
Vaginal progesterone is recommended for women with short cervix (≤20 mm) before 24 weeks' gestation, and may be considered for cervical length 21-25 mm based on shared decision-making (GRADE 1B evidence) 1
Cerclage placement, progesterone administration, or pessary placement may be considered to decrease preterm birth rates, but 17-alpha hydroxyprogesterone caproate and cerclage are not recommended for treatment of short cervix in singleton pregnancies 1

Transvaginal ultrasound cervical length assessment is a strong predictor of spontaneous preterm birth, with a positive predictive value of 16.2% for birth before 37 weeks and 7.4% for birth before 32 weeks for a midtrimester cervical length ≤25 mm 1
Short cervix is associated with significant perinatal morbidity and mortality due to preterm birth 1
Patients at risk for cervical insufficiency include those with prior mid-trimester pregnancy losses, prior extreme preterm deliveries, previous cervical trauma, prior cervical lacerations during delivery, congenital uterine anomalies, prior trachelectomy, and exposure to diethylstilbestrol (DES) 3

In twin pregnancies, cervical length measuring <1.5 cm between 15-24 weeks is predictive of preterm labor, according to the American College of Radiology 4
Routine transvaginal cervical length screening is not recommended after 25-26 weeks' gestational age in multiple gestations 4
Progesterone, pessary, or cerclage are not recommended for treatment of cervical shortening in twin gestations outside clinical trials (GRADE 1B evidence) 1

17-alpha hydroxyprogesterone caproate, cerclage placement in the absence of cervical dilation, and cervical pessary are not recommended for treatment of short cervix in singleton pregnancies 1
Women with cervical insufficiency should avoid moderate-to-vigorous physical activity, and potentially complete light upper-body resistance exercise 3