Obstetric history
A history of multiple second-trimester losses, preceded by painless cervical dilation, is an indication for a history-indicated cerclage in a singleton pregnancy. Painless cervical dilation is defined by cervical dilation in the absence of contractions, labor, ruptured membranes, infection, or other clear pathology.
There is currently no recommendation for cerclage placement for obstetric history in current multiple gestations.
Transvaginal ultrasound cervical length (during pregnancy)
A short transvaginal ultrasound cervical length in the second trimester is associated with an increased risk of preterm delivery and may be a precursor to cervical insufficiency. Short cervical length is thought to be on the continuum of cervical insufficiency and a precursor to preterm labor and delivery (3). Given the significantly increased risk of preterm delivery in women with a short cervix and prior preterm birth, another definition of cervical insufficiency is a transvaginal ultrasound cervical length <25 mm before 24 weeks in a woman with a prior spontaneous preterm birth (4).
Physical examination
Current painless cervical dilation in a singleton pregnancy 16 0/7 to 23 6/7 is another definition of cervical insufficiency and indication for cerclage.
Physical examination for cervical dilation may include a sterile speculum examination for visual dilation and a sterile vaginal examination for evaluation of physical cervical dilation.
Before cerclage placement, other causes for cervical dilation must be ruled out as they are contraindications to cerclage placement, including
Abruption
Active preterm labor
Preterm premature rupture of membranes
Suspicion for chorioamnionitis/intraamniotic infection
Obstetric history: Both vaginal progesterone and 17-hydroxyprogesterone caproate are effective in the prevention of recurrent preterm birth in women with a history of preterm delivery 20 0/7 to 36 6/7 weeks (7).
Ultrasound: Vaginal progesterone is effective in the management of short cervix on transvaginal ultrasound (7).
Examination: There are no other interventions that are recommended for preterm birth prevention in the setting of cervical dilation (2).
The technique for transvaginal ultrasound cervical length measurement has been described previously (8), and there is an educational/certification program available through the Perinatal Quality Foundation to ensure accurate cervical length measurement (https://clear.perinatalquality.org/default.aspx) (Figure 3.7.1).
Table 3.7.1 highlights perioperative considerations for cerclage placement.
Gestational age: Cerclage should be placed before 24 weeks’ gestation. A transabdominal cerclage placed in pregnancy would ideally be placed before 12 weeks’ gestation. A history-indicated cerclage is optimally placed at 10 to 14 weeks’ gestation, and an ultrasound- or examination-indicated cerclage should be placed as soon as possible after diagnosis.
Fetal ultrasound: Ultrasound documenting viable intrauterine pregnancy should be done before and after cerclage placement.
Amniocentesis: May be considered before examination-indicated cerclage owing to an increased rate of asymptomatic culture-positive amniotic fluid (2). Amniocentesis before cerclage placement has not been shown to have an adverse impact on outcomes, its benefit is unclear and may be offered after discussion with the patient regarding risks/benefits.
Indomethacin: Perioperative indomethacin, along with antibiotics, improved outcomes in the setting of examination-indicated cerclage placement (9), its use is recommended perioperatively (50 mg PO q8h for 48 hours). Given the continuum of cervical shortening to cervical dilation, perioperative indomethacin may be considered for an ultrasound-indicated cerclage as well (Table 3.7.1).
Figure 3.7.1. Demonstration of transvaginal ultrasound cervical length measurement. (Reprinted from Perinatal Quality Foundation. CLEAR Cervical Length Education and Review. https://clear.perinatalquality.org/default.aspx)
Table 3.7.1 Perioperative Considerations for Cerclage Placement
Considerations
History Indicated (Transabdominal)
History Indicated (Transvaginal)
Ultrasound Indicated (Transvaginal)
Examination Indicated (Transvaginal)
Indication
Prior preterm birth and lack of accessible cervix vaginally due to prior cervical surgery or malformation (<32 weeks)
Painless cervical dilatation leading to recurrent second-trimester loss
Prior examination-indicated OR prior ultrasound-indicated cerclage with subsequent preterm delivery ≤32 weeks*
Prior preterm birth (16 0/7-36 6/7 weeks) and current second-trimester transvaginal ultrasound cervical length <25 mm
Painless cervical dilation <24 weeks (without labor, membrane rupture, abruption, chorioamnionitis)
Timing
Prepregnancy or before 12 weeks
11-15 weeks
Before 24 weeks
Before 24 weeks
Fetal ultrasound
Yes
Yes
Yes
Yes
Amniocentesis
No
No
No
Consider
Perioperative indomethacin
No
No
Consider
Yes
Perioperative antibiotics
No
No
Consider
Yes
Anesthesia
General endotracheal or spinal
Spinal
Spinal
Spinal
Postoperative management
Outpatient**
Outpatient
Outpatient
Outpatient
Bed rest
No
No
No
No
* For women with a prior ultrasound- or examination-indicated cerclage and subsequent ≥33 weeks delivery, history-indicated cerclage or management with serial cervical length may be offered.
** For open abdominal procedure, immediate postoperative management is inpatient; for laparoscopic/robotic procedures, immediate postoperative management may be in- or outpatient.
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