A cervical cerclage is a surgical procedure performed during pregnancy to prevent premature birth. It places a temporary stitch around the cervix to provide mechanical support and keep the opening closed. The cerclage is placed to counter cervical insufficiency, a condition where the cervix shortens or opens too early under the weight of the growing pregnancy. The possibility of the “water breaking,” medically known as Premature Rupture of Membranes or PROM, remains a serious concern even with this protective measure in place.
What is a Cervical Cerclage and Why is it Placed
A cervical cerclage is a surgical suture placed high on the cervix to reinforce it. This procedure maintains the structural integrity of the cervix and prolongs the pregnancy. The primary reason for placement is cervical insufficiency, where the cervix is weak and may dilate prematurely, potentially leading to a second-trimester loss or preterm birth.
The procedure is most often recommended for women with a history of prior second-trimester losses linked to cervical issues or those found to have a significantly short cervix on ultrasound during the current pregnancy. Two main transvaginal techniques exist: the McDonald method, which uses a purse-string stitch around the outer portion of the cervix, and the Shirodkar technique, which places the suture higher up and often involves burying the knot.
Premature Rupture of Membranes (PROM) with a Cerclage
Despite the cerclage’s function as a mechanical barrier, the reality is that Premature Rupture of Membranes (PROM) can still occur. A cerclage is designed to prevent the cervix from opening but cannot entirely prevent the membranes from weakening and rupturing. The rate of preterm PROM (PPROM) in women with a cerclage in place has been reported to be as high as 38% in some studies.
The rupture can happen for several reasons, including the mechanical pressure of the pregnancy causing the membranes to bulge and tear just above the stitch. Another significant pathway involves ascending infection, where bacteria travel up the vagina and around the suture material. This infectious process can trigger inflammation, which weakens the amniotic sac and leads to rupture.
The increased risk of chorioamnionitis, an infection of the amniotic fluid and membranes, is a central concern. Because the cerclage suture is a foreign body, it can act as a pathway for bacteria. This makes the risk of intrauterine infection nearly double compared to PROM without a cerclage.
Identifying Symptoms and Immediate Action
Identifying the symptoms of ruptured membranes is important, especially when a cerclage is present. The most noticeable symptom of PROM is a sudden gush or a persistent trickle of warm fluid from the vagina. This fluid is typically clear or light yellow and will continue to leak, as the body constantly produces amniotic fluid.
It can be difficult to distinguish amniotic fluid from urine or an increase in normal vaginal discharge, which is common in pregnancy. Amniotic fluid often has a distinct, mildly sweet smell and soaks through clothing, unlike temporary discharge or a small amount of urine. Any suspicion of fluid leakage, particularly if accompanied by pelvic pressure, contractions, or foul-smelling discharge, demands immediate medical attention.
Immediate action involves contacting the healthcare provider or presenting to the hospital labor and delivery unit without delay. Patients should avoid inserting anything into the vagina, including tampons, and refrain from sexual intercourse to prevent introducing infection. Prompt evaluation is necessary to confirm the diagnosis and assess for any signs of infection or labor.
Clinical Management Following PROM
Once Premature Rupture of Membranes is confirmed in a patient with a cerclage, the clinical management involves a delicate balance between prolonging the pregnancy and minimizing the risk of severe infection. The crucial decision involves the timing of cerclage removal. The presence of the stitch after PROM significantly increases the risk of chorioamnionitis and maternal sepsis, which can be life-threatening.
Immediate cerclage removal is often the preferred therapeutic approach because retaining the stitch can nearly double the rate of clinical infection. While retaining the cerclage may slightly prolong the time until delivery, this benefit is generally outweighed by the increased maternal risk of infection. Removal is typically done quickly unless the clinical team opts for a short delay to administer antenatal corticosteroids for fetal lung maturity.
Following cerclage removal and depending on the gestational age, expectant management begins, which includes continuous monitoring for signs of infection and preterm labor. Patients are usually given a course of antibiotics to prevent infection and may receive corticosteroids if the pregnancy is before 34 weeks, which helps mature the baby’s lungs. Magnesium sulfate may also be administered for neuroprotection if delivery is anticipated before 32 weeks.