An abdominal cerclage is a specialized surgical procedure designed to prevent recurrent pregnancy loss or preterm birth caused by cervical insufficiency, a condition where the cervix painlessly opens too early during pregnancy. This weakness in the cervix, often occurring in the second trimester, means the cervix cannot support the growing weight of the fetus, leading to miscarriage or very early delivery. The procedure involves placing a strong, permanent stitch high on the cervix to provide mechanical support and keep the cervical opening securely closed. Unlike the more common vaginal cerclage, the abdominal approach is a more aggressive and invasive intervention reserved for the most challenging cases of cervical insufficiency.
Defining the Procedure and Purpose
The physical mechanism of the abdominal cerclage centers on placing a synthetic band at the narrowest and strongest part of the cervix, known as the cervicoisthmic junction or the level of the internal os. The higher placement provides superior structural integrity because it bypasses the weaker, more pliable tissue of the lower cervix. The suture material used is a woven, non-absorbable tape, typically made of a highly durable and tissue-compatible synthetic material like polypropylene or Mersilene. To place the stitch, surgeons must carefully dissect the anatomical space around the cervix, often by creating a “bladder flap” and identifying the uterine vessels. The non-absorbable band is then securely tied in a purse-string fashion, creating a permanent barrier to prevent the cervix from dilating under the increasing pressure of the pregnancy.
When Abdominal Cerclage is Necessary
An abdominal cerclage is not typically a first-line treatment for cervical insufficiency, but rather a targeted intervention for patients with specific, high-risk conditions. The most common indication is a history of a failed transvaginal cerclage (TVC), defined as a pregnancy loss or delivery before 28 to 34 weeks of gestation despite a well-placed TVC. Another primary indication is an anatomical limitation that makes a transvaginal approach impossible or ineffective. This includes structural damage to the cervix resulting from prior extensive surgical procedures, such as a large loop electrosurgical excision procedure (LEEP), a cone biopsy, or a trachelectomy, which is the removal of the cervix. The resulting extremely short, scarred, or absent cervical tissue prevents a vaginal cerclage from being securely or functionally placed.
Comparing Abdominal vs. Vaginal Cerclage
The fundamental difference between the two cerclage types lies in their placement location and intended permanence. A transvaginal cerclage (TVC) is placed through the vagina, accessing the lower portion of the cervix. This approach is less invasive and is often placed electively in the early second trimester or, in some situations, as an emergency procedure when the cervix is already beginning to open.
In contrast, the abdominal cerclage (AC) is placed much higher, at the cervicoisthmic junction, which requires an abdominal surgical approach. The preferred timing for AC is often pre-conception or in the early first trimester, before the uterus becomes too large, although it can be placed up to about 14 weeks of gestation. The AC’s high placement and permanent material provide a far more robust mechanical barrier than the TVC, leading to higher success rates in patients with severe cervical insufficiency, with neonatal survival rates reported to be over 90%.
A major distinction concerns removal and delivery: a TVC is temporary, typically removed around 37 weeks of gestation to allow for a potential vaginal delivery. The AC, however, is a permanent fixture left in place until delivery, and it can remain for future pregnancies. Consequently, any pregnancy following an AC placement requires delivery via Cesarean section.
Placement and Post-Procedure Management
The abdominal cerclage is placed using either an open laparotomy, which involves a larger incision, or increasingly, a minimally invasive laparoscopic approach using small incisions and specialized instruments. The laparoscopic technique is now the preferred method due to its lower morbidity, reduced blood loss, and faster recovery time, provided the surgeon has the necessary expertise. The ideal time for placement is before a woman is pregnant, known as the pre-pregnancy or interval procedure, because the non-pregnant uterus is smaller and less vascular, simplifying the procedure.
Once the stitch is secured, a unique aspect of post-procedure management is the mandatory requirement for Cesarean delivery. Because the cerclage is placed so high on the cervix, it cannot be safely accessed or removed through the vagina. The AC is left intact during the C-section delivery, allowing the mother to retain the stitch for any future pregnancies, which also must be delivered by C-section. If a patient decides they are finished with childbearing, the cerclage can be removed during the final C-section or later via another laparoscopic procedure.