Cervical insufficiency is an important cause of preterm birth and complicates up to 1% of pregnancies. It is typically diagnosed as painless cervical dilation without contractions, often in the second trimester at around 16-18 weeks, but the clinical presentation can be variable. In some cases, a rescue cerclage can be placed to prevent second trimester loss or preterm birth.
Dr. Jon I. Einarsson
A recent landmark randomized controlled trial of abdominal vs. vaginal cerclage – the MAVRIC trial (Multicentre Abdominal vs. Vaginal Randomized Intervention of Cerclage)1 published in 2020 – has offered significant validation for the belief that an abdominal approach is the preferred approach for patients with cervical insufficiency and a prior failed vaginal cerclage.
Obstetricians traditionally have had a high threshold for placement of an abdominal cerclage given the need for cesarean delivery and the morbidity of an open procedure. Laparoscopic abdominal cerclage has lowered this threshold and is increasingly the preferred method for cerclage placement. Reported complication rates are generally lower than for open abdominal cerclage, and neonatal survival rates are similar or improved.
In our experience, the move toward laparoscopic abdominal cerclage is largely a patient-driven shift. Since 2007, at Brigham and Women’s Hospital in Boston, we have performed over 150 laparoscopic abdominal cerclage placements. The majority of patients had at least one prior second-trimester loss (many of them had multiple losses), with many having also failed a transvaginal cerclage.
In an analysis of 137 of these cases published recently in Fertility and Sterility, the neonatal survival rate was 93.8% in the 80 pregnancies that followed and extended beyond the first trimester, and the mean gestational age at delivery was 36.9 weeks.2 (First trimester losses are typically excluded from the denominator because they are unlikely to be the result of cervical insufficiency.)
History and outcomes data
The vaginal cerclage has long been a mainstay of therapy because it is a simple procedure. The McDonald technique, described in the 1950s, uses a simple purse string suture at the cervico-vaginal juncture, and the Shirodkar approach, also described in the 1950s, involves placing the cerclage higher on the cervix, as close to the internal os as possible. The Shirodkar technique is more complex, requiring more dissection, and is used less often than the McDonald approach.
The abdominal cerclage, first reported in 1965,3 is placed higher on the cervix, right near the juncture of the lower uterine segment and the cervix, and has generally been thought to provide optimal integrity. It is this point of placement – right at the juncture where membranes begin protruding into the cervix as it shortens and softens – that offers the strongest defense against cervical insufficiency.
The laparoscopic abdominal approach has been gaining popularity since it was first reported in 1998.4 Its traditional indication has been after a prior failed vaginal cerclage or when the cervix is too short to place a vaginal cerclage – as a result of a congenital anomaly or cervical conization, for instance.
Some of my patients have had one pregnancy loss in which cervical insufficiency was suspected and have sought laparoscopic abdominal cerclage without attempting a vaginal cerclage. Data to support this scenario are unavailable, but given the psychological trauma of pregnancy loss and the minimally invasive and low-risk nature of laparoscopic abdominal cerclage, I have been inclined to agree to preventive laparoscopic abdominal procedures without a trial of a vaginal cerclage. I believe this is a reasonable option.
The recently published MAVRIC trial included only abdominal cerclages performed using an open approach, but it provides good data for the scenario in which a vaginal cerclage has failed.
The rates of preterm birth at less than 32 weeks were significantly lower with abdominal cerclage than with low vaginal cerclage (McDonald technique) or high vaginal cerclage (Shirodkar technique) (8% vs. 33%, and 8% vs. 38%). No neonatal deaths occurred.
The analysis covered 111 women who conceived and had known pregnancy outcomes, out of 139 who were recruited and randomized. Cerclage placement occurred either between 10 and 16 weeks of gestation for vaginal cerclages and at 14 weeks for abdominal cerclages or before conception for those assigned to receive an abdominal or high vaginal cerclage.
Reviews of the literature done by our group1 and others have found equivalent outcomes between abdominal cerclages placed through laparotomy and through laparoscopy. The largest systematic review analyzed 31 studies involving 1,844 patients and found that neonatal survival rates were significantly greater in the laparoscopic group (97% vs. 90%), as were rates of deliveries after 34 weeks of gestation (83% vs. 76%).5
The better outcomes in the laparoscopic group may at least partly reflect improved laparoscopic surgeon techniques and improvements in neonatal care over time. At the minimum, we can conclude that neonatal outcomes are at least equivalent when an abdominal cerclage is placed through laparotomy or with a minimally invasive approach.