A cervical cerclage is a surgical procedure where a stitch is placed around the cervix, the lower part of the uterus. Its purpose is to provide structural support to keep the cervix closed during pregnancy, helping to prevent it from opening too early and leading to premature birth. While cerclage is a recognized treatment in singleton pregnancies, its use in twin pregnancies is more complex due to the increased physical demands of carrying multiple fetuses.
Indications for Cerclage in Twin Pregnancies
The primary reason for a cerclage is cervical insufficiency, where the cervix begins to shorten and open prematurely without contractions. Twin pregnancies increase this risk due to the greater weight and pressure on the cervix, making it more prone to shortening. Cervical length is monitored through transvaginal ultrasound in these higher-risk pregnancies.
There are three main scenarios for recommending a cerclage. A history-indicated cerclage is for individuals with previous second-trimester pregnancy losses from cervical insufficiency. This proactive cerclage is performed between 13 and 16 weeks of gestation.
An ultrasound-indicated cerclage is advised when an ultrasound before 24 weeks reveals a short cervix, defined as less than 25 millimeters. This finding suggests the cervix may not support the pregnancy to term. The procedure is more strongly considered if the length is under 15 mm.
A rescue or emergent cerclage is performed when the cervix has already started to dilate painlessly, often discovered during a physical exam. The goal is to close the opening cervix to prolong the pregnancy and may be accompanied by other treatments like antibiotics.
The Cerclage Procedure
The cerclage procedure is performed in a hospital and is typically completed in under an hour. It is carried out under regional anesthesia, such as a spinal or epidural block, though general anesthesia is also an option.
The most common technique is the McDonald cerclage, which involves placing a non-absorbable suture around the cervix in a “purse-string” fashion. A surgeon passes the suture through the cervical tissue, encircles it, and tightens it to close the internal opening before tying a knot.
This procedure is performed during the second trimester, between 12 and 24 weeks. The specific timing depends on whether the cerclage is based on a patient’s history, an ultrasound finding, or an emergent situation.
Efficacy and Risks in Twin Pregnancies
The effectiveness of cervical cerclage in twin pregnancies is debated, and research findings have been inconsistent. Unlike in singleton pregnancies, its benefits are not as clearly established. Some studies suggest cerclage can prolong pregnancy in specific subgroups, such as for women with a very short cervix (less than 15mm) or a dilated cervix.
The procedure has risks that must be weighed against potential benefits. These include infection, premature rupture of membranes (the “water breaking”) from the needle, and the possibility of stimulating uterine contractions that could lead to preterm labor.
Some past studies have suggested that in certain twin pregnancies, cerclage might lead to an earlier delivery. The decision is highly individualized and considers the patient’s obstetric history, cervical length, and any dilation. An emergency cerclage for a dilated cervix before 24 weeks may be a viable option in specific scenarios.
Post-Procedure Management and Removal
After the cerclage placement, patients are monitored in the hospital for a few hours to a day for contractions or other complications. Light bleeding or cramping for a few days is normal. Aftercare instructions include modified activity and pelvic rest, which means abstaining from intercourse.
Regular follow-up appointments are scheduled to monitor the stitch and pregnancy health, sometimes including ultrasounds. Patients should contact their healthcare provider immediately for any of the following symptoms:
- Contractions
- Bleeding
- Fever
- Leakage of fluid
The cerclage is removed around 36 to 37 weeks of gestation to allow labor to begin naturally. Removal is a quick procedure done in a doctor’s office and does not require anesthesia. If a cesarean delivery is planned, the stitch may be removed in the operating room. The cerclage will be removed earlier if signs of preterm labor or infection develop.