A cerclage is a stitch placed around the cervix during pregnancy to hold it closed and prevent premature birth or pregnancy loss. The cervix normally stays firm and closed until late pregnancy, then gradually softens and opens for delivery. In some women, the cervix shortens or opens too early, putting the pregnancy at risk. A cerclage reinforces the cervix so it can support the pregnancy longer, typically until 36 to 37 weeks, when the stitch is removed.
Why a Cerclage Might Be Recommended
There are three main scenarios where a cerclage is used, each based on different warning signs.
History-based cerclage: If you’ve had three or more preterm deliveries or mid-pregnancy losses, your doctor may recommend a cerclage before any symptoms appear. This is a preventive measure placed early in pregnancy based purely on your past obstetric history.
Ultrasound-based cerclage: During routine monitoring, if your cervix measures shorter than 25 millimeters and you’ve had at least one prior preterm birth or mid-pregnancy loss, a cerclage is typically offered. For twin pregnancies, the threshold is even shorter, with evidence suggesting benefit when the cervix is under 15 millimeters. These cerclages are placed before 24 weeks of pregnancy.
Rescue cerclage: This is the most urgent scenario. If the cervix has already opened and the amniotic membranes are bulging through, a rescue cerclage may be attempted on a case-by-case basis. This carries higher risk of infection for both mother and baby, but it can extend the pregnancy significantly when successful.
How the Procedure Works
Most cerclages are placed through the vagina under regional or general anesthesia. The two main techniques differ in where exactly the stitch sits on the cervix.
The McDonald technique is the most common approach. The surgeon places a purse-string suture around the outside of the cervix without needing to move any tissue out of the way. It’s relatively straightforward and the stitch can be removed easily in the office later in pregnancy.
The Shirodkar technique places the stitch higher on the cervix. This requires slightly more dissection but positions the suture closer to where the cervix meets the uterus. It’s often chosen when a previous McDonald cerclage failed during an earlier pregnancy, or when the cervix is very short and doesn’t leave enough room for a lower stitch. Despite being placed higher, a Shirodkar cerclage still allows for vaginal delivery after removal.
When a Transabdominal Approach Is Needed
A small number of women can’t have a cerclage placed through the vagina at all. This includes women with an extremely short cervix after previous surgery (such as a large cone biopsy), an anatomically altered cervix, or those whose prior vaginal cerclage failed. In these cases, the stitch is placed through the abdomen, either through a traditional incision or laparoscopically.
A transabdominal cerclage can be placed before pregnancy or during early pregnancy. Some surgeons prefer to place it before conception so the stitch is already in position. Because this type of cerclage is permanent and not easily removed, delivery is by cesarean section.
When the Stitch Is Placed
Timing matters. Elective cerclages placed between 14 and 18 weeks of pregnancy produce the best outcomes compared to those placed later. Research comparing early placement (14 to 18 weeks) with later placement (19 to 27 weeks) found that the earlier window led to more favorable pregnancy outcomes overall.
Emergency cerclages, by definition, happen whenever the problem is discovered, sometimes well into the second trimester. These carry more risk than planned procedures but can still be effective.
How Effective Cerclage Is
The benefit of cerclage depends heavily on choosing the right patients. For women with three or more prior preterm deliveries, a preventive cerclage roughly cuts the rate of very early preterm birth (before 33 weeks) in half, from about 32% down to 15%. That’s a meaningful difference in outcomes for the baby, since every additional week in the womb at that stage matters enormously.
For women with a very short cervix under 15 millimeters, a large pooled analysis found that cerclage reduced the rate of preterm birth before 34 weeks by about 26%. The procedure is not a guarantee, but for women who meet the criteria, the numbers clearly favor it.
Risks and Complications
The most common complication is premature rupture of membranes, meaning your water breaks early. In one large review of 482 cases, this ultimately occurred in 38% of patients, though this figure reflects a population that was already at very high risk for preterm birth to begin with.
Infection is less common but more serious. The overall infection rate in that review was about 6.6%, but the risk varied dramatically depending on the situation. Women who had an emergency cerclage faced a 12.7% infection rate compared to 4.7% for those who had a planned procedure. Cervical dilation at the time of surgery also mattered: women whose cervix was already open more than 2 centimeters had an infection rate above 40%, while those at 2 centimeters or less had a rate under 6%.
Other possible complications include cervical tearing if labor starts while the stitch is still in place, which is one reason doctors aim to remove it before full-term labor begins.
Recovery After Placement
Recovery is relatively quick. According to the American College of Obstetricians and Gynecologists, you can expect some spotting or light bleeding for up to three days, an increase in clear vaginal discharge, and a few days of mild cramping. You should avoid heavy activity for the first few days and check with your provider before resuming sex. Nothing should be placed in the vagina while you’re healing.
Beyond the initial recovery, many women with a cerclage continue with a modified activity level for the rest of pregnancy, though specific restrictions vary by provider and individual risk.
When the Stitch Comes Out
Vaginal cerclages are typically removed between 36 and 37 weeks. At this point the baby is considered early term and the risk of complications from prematurity is low. Removal is usually done in the office or clinic without anesthesia, since the stitch is accessible through the vagina.
Sometimes the cerclage needs to come out earlier than planned. This happens if labor appears imminent, if the membranes rupture prematurely, or if there’s another complication. Women who had an emergency cerclage are at higher risk of needing early, unscheduled removal. Leaving the stitch in place during active labor is avoided because it can cause cervical lacerations or, in rare cases, uterine injury.
After removal, some women go into labor within days, while others carry for another few weeks until their due date. The cerclage itself doesn’t trigger labor, so the timing varies.