Ultrasound evaluation of the cervix is an essential step in managing cervical insufficiency. For an accurate measure, the cervical length should be evaluated transvaginally⁽⁴⁾. The evaluation should be done following a standardized protocol. The key points of the ultrasound examination are as follows: the maternal bladder should be empty, to avoid artificial elongation of the cervix. Also, excessive pressure applied on the transducer can artificially create a longer cervix. The cervix should occupy 50-70% of the screen. The most important structures that need to be identified are the internal and external os and the cervical canal. The cervix length is the dista­nce between the internal and external os. The measurement should be repeated at least three times and the shortest correct measurement should be recorded and used for clinical management.

When feasible, transvaginal measurement of the cervical length should be carried out at the second-trimester anatomy scan^(1,5).

Knowing the natural evolution of the cervical length during pregnancy is important. Usually, the length of the cervix is stable between 14 to 18 weeks of pregnancy⁽⁶⁾, with a median length of 43 mm at 16 weeks which shortens to about 31 mm at 36 weeks of gestation. African and Asian women, as well as younger women and with lower Body Mass Index present with a shorter median length of the cervix in the second trimester⁽⁷⁾.

Management of cervical insufficiency
and indications of cervical cerclage

Depending on the cervical length and the presence of additional risk factors, the management of a short cervix relies upon prophylactic vaginal progesterone or cervical cerclage.

In asymptomatic women without a previous spontaneous preterm birth, with a cervical length below 25 mm, vaginal progesterone should be prescribed daily until 36 weeks⁽⁸⁾. A transvaginal scan of the cervix should be carried out every 1-2 weeks to identify further shortening of the cervix. When the patient is already on vaginal progesterone, but cervical length drops below 10 mm, the woman should receive a vaginal cerclage^(9,10).

In asymptomatic women who present with a history of premature birth, already taking vaginal progesterone, but develop a short cervix (<25 mm), placing a cervical cerclage is the next step indicated⁽¹¹⁾. The two scenarios mentioned above are the ultrasound-indicated cer­clage, performed when cervical shortening is detected on transvaginal ultrasound, usually between 14 and 24 weeks of gestation⁽¹⁾.

Three other types of cervical cerclage are commonly performed⁽¹²⁾. History-indicated cerclage is typically inserted between 11 and 14 weeks of pregnancy as a preventative measure based on the woman’s previous obstetric history. Several studies have also revealed the benefit of this type of cerclage. When placed at 12-14 weeks, the prophylactic vaginal cerclage is associated with a reduction in premature birth for women with a prior preterm birth^(13,14). Emergency cerclage is carried out when cervical dilatation has already begun and is defined as being performed when the membranes are exposed, either through clinical symptoms such as vaginal discharge or bleeding, or observed on ultrasound. It is associated with favorable obstetrical and neonatal outcomes when compared to expectant management, decreasing neonatal deaths and preterm births^(15,16). Transabdominal cerclage is placed at the cervicoisthmic junction, either laparoscopically or via laparotomy, and can be performed before the pregnancy or during the first trimester⁽¹⁷⁾.

Current evidence does not recommend the use of cervical pessaries in the management of cervical insufficiency, regardless of obstetric history, concurrent use of vaginal progesterone, or the severity of cervical length shortening^(18-20).

A cerclage is generally performed using a vaginal approach, with the most common techniques being adaptations of those first described by McDonald and Shirodkar. A McDonald cerclage involves placing a non­absorbable suture at the cervicovaginal junction, while the Shirodkar method entails dissecting the vesicocervical mucosa to position a nonabsorbable suture as close to the cervical internal os as possible^(21,22). Research indicates no significant advantage of one technique or suture type over another regarding the effectiveness of preventing preterm birth. Moreover, a recent meta-analysis recommended the McDonald technique, because it is easy to place and remove the stitch, along with comparable efficacy to the Shirodkar approach⁽²³⁾.

There is also the option of placing a cerclage transabdominal, a technique first described by Benson and Durfee in 1965⁽²⁴⁾. Placement of the transabdominal cerclage involves a more complex and higher-risk surgery compared to transvaginal cerclage, as it requires abdominal access and dissection, leading to increased bleeding risks. Women with transabdominal cerclage will require a caesarean delivery, exposing the patient to another surgical procedure.

However, transabdominal cerclage has certain important advantages: it enhances structural support by placing the stitch at the cervicoisthmic junction, and it minimizes the risks that come with the presence of a vaginal foreign body, thus reducing the likelihood of PPROM⁽²⁵⁾.

Indications of transabdominal cerclage

Transabdominal cerclage is not generally proposed as the first treatment option for women with cervical insufficiency. This is because of its higher morbidity associated with placement and the necessity for caesa­rean delivery. A transabdominal cerclage is proposed as a treatment option for patients where the anatomy of the cervix would make the placing of a cerclage very difficult or for patients who have a history of failed vaginal cerclage.

A transabdominal cerclage is advisable for anatomical reasons in specific situations. These include patients with an extensively amputated cervix, such as those who have undergone recurrent LEEP procedures or trachelectomy, as well as patients with a congenitally very short cervix⁽²⁶⁾.

Women who had a failed vaginal cerclage in a previous pregnancy are also candidates for the transabdominal cerclage, especially those who were confronted with a preterm birth before 28 weeks of pregnancy.

David et al. conducted a retrospective study aiming to compare how a succeeding transabdominal or a transvaginal cerclage influences the incidence of premature birth in patients with a history of failed vaginal cerclage, who gave birth before 33 to 34 weeks despite having a vaginal cerclage. The study indicated the favorable effect of the transabdominal cerclage, which was associated with a reduction in the rate of preterm birth among the studied population⁽²⁷⁾.

In a large RCT, Shennan et al. compared a low vaginal cerclage with a transabdominal cerclage and proved the superiority of the latest. Women were assigned in three groups: transabdominal cerclage, high and low vaginal cerclage. All women had a history of failed vaginal cerclage. The rate of preterm birth below 32 weeks of pregnancy was significantly lower in the group of women who received a transabdominal cerclage compared to the group who received the low vaginal cerclage (8% versus 33%)⁽²⁸⁾. MAVRIC represented the first RCT to compare a transabdominal cerclage to a vaginal cerclage.

To further investigate which patients would benefit most from an abdominal cerclage, Abdulrahman et al. conducted a retrospective study with subgroup analysis on the topic of surgical and obstetrical outcomes after pre- and postconceptional placement of laparoscopic abdominal cerclage. Patients who were offered an abdominal cerclage were divided into three categories based on the indication: patients with prior cervical surgery, patients with a history of failed vaginal cerclage, and patients with other indications, such as several dilatation and curettage procedures and/or multiple fetal losses in the second or third trimester due to cervical insufficiency, without failed vaginal cerclage. Delivery after 34 weeks was the primary outcome measure. Pregnancy rates after preconception intervention, fetal survival rates, and other obstetrical complications are counted as secondary outcome measures. Complications were minor and rare (2.2%). The pregnancy rate after pre-conceptional placement of abdominal cerclage was 74.1%. A high number of patients delivered after reaching 34 weeks (90.5%). Cases of fetal loss in the second trimester only occurred in the group of women with cerclage placed because of a history of previously failed cerclage. The retrospective study highlighted the safety and efficiency of abdominal laparoscopic cerclage in patients⁽²⁹⁾.

Transabdominal cerclage techniques

A transabdominal cerclage can be placed either by laparotomy or by laparoscopy.

The abdominal approach to cervical cerclage was first introduced by Benson and Durfee in 1965, and it boasts a reported success rate of 85% to 90%⁽²⁴⁾.

In the open approach, the surgery begins with a Pfannenstiel typically performed under spinal analgesia. The uterus is exteriorized, allowing for the identification and palpation of the uterine vessels. An avascular space is created between the uterus and the uterine vessels. This space needs to be at the level of the internal cervical os. A nonabsorbable, thick braided 5-mm suture is typically passed through this space with a right-angle clamp. The suture can be tied either anteriorly or posteriorly and is left in place. Current research does not support the use of tocolysis during transabdominal cerclage placement. The open technique for transabdominal cerclage mandates two laparotomies: one for the cerclage placement and another for caesarean delivery. Placement of a transabdominal cerclage using the open approach is associated with risks that are comparable to those of other open surgical procedures. Additionally, the hospital admission and recovery times are similar to those required for other open surgeries⁽³⁰⁾.

In the last decade, a minimally invasive approach for transabdominal cerclage placement has been developed and has become more popular. It can be performed either by conventional laparoscopy, robotic surgery or single-incision laparoscopy.

The advantages of minimally invasive laparoscopic trans­abdominal cervical cerclage over the traditional abdominal approach have been highlighted by several authors. Patients who are offered the laparoscopic approach have reduced perioperative complications, need smaller incisions, and suffer less postoperative pain. Moreover, the duration of hospital admission is shorter and the recovery time is quicker. From a technical point of view, laparoscopy enhances access to the anatomical regions the surgeon operates on, such as the paracervical spaces and the posterior cervical isthmus. This is especially important when the surgery is done during pregnancy.

Thus, laparoscopic transabdominal cerclage has become the preferred option in many tertiary care centers, contingent on the availability of surgical expertise, with success rates ranging from 79% to 100%⁽³¹⁾, comparable to those of laparotomy⁽³²⁾.

The fundamental principle of performing laparoscopic transabdominal cerclage is consistent, whether done during pregnancy or pre-pregnancy. However, the presence of a gravid uterus and the lack of a vaginal manipulator present distinct challenges during the procedure.

Various laparoscopic methods have been reported in non-pregnant patients, with most using a three-port approach, and some using a fourth suprapubic assistant port. Typically, a nonabsorbable, thick braided 5-mm suture, a straightened needle, and a uterine manipulator are used. One of the most common methods is the Broad Ligament Window technique. The steps of this procedure can be studied in the papers of Ramesh et al.⁽³³⁾ Suff et al. published a paper in 2020 on the topic of developing a video to teach surgeons how to place a transabdominal cerclage. They created an 8-minute video with audio narration that outlines the insertion and management of an abdominal cerclage, making it freely available to clinicians interested in learning this procedure⁽³⁴⁾.

Wang et al. described a novel technique of modified laparoscopic transabdominal cerclage placement, where the nonabsorbable thick braided suture is tied in the vagina, thus making removal of the stitch possible at term and allowing for an attempt of vaginal delivery. The authors conducted a study on this technique among 26 patients, which resulted in favorable obstetrical outcomes, including neonatal survival of 100%, term delivery rate of 81.5%, and vaginal delivery in 21 cases⁽³⁵⁾. However, despite the value of vaginal birth, there are benefits of using a single transabdominal cerclage for subsequent pregnancies, that can be left in place when delivering via caesarean section. More prospective studies are needed on this subject.

When surgery is performed on a pregnant patient, there is always a possible risk of miscarriage or rupture of membranes. Performing the surgery before pregnancy removes the risks mentioned before. In this situation, when the cerclage is placed before pregnancy, fetal survival rate is as high as 90%, and the incidence of complications is low. Current research and guidelines on laparoscopic cerclage support either approach, since fetal outcomes are comparable⁽³⁶⁾.

Both laparoscopic and open transabdominal cerclage placement techniques yield possible complications, such as pelvic infections, lacerations of the uterine vessels, injury of the bladder or insufficient tightening of the cerclage. According to available research, complication rates are similar for both types of surgical approaches and are usually minor. Rare cases of uterine dehiscence or spontaneous uterine rupture have also been described^(24,25).

Managing a pregnancy with an abdominal cerclage

Managing a pregnant patient who has an abdominal cerclage in place can be a challenge in itself. Current guidelines do not recommend follow-up of cervical length, because a rescue cerclage would not enhance outcomes for a patient with cervical shortening after an initial transabdominal cerclage. A rescue cerclage may be even more complex and less likely to succeed, considering the anatomical factors and patient history that necessitated the abdominal cerclage in the first place⁽³⁹⁾. It is unclear whether supplementing with vaginal progesterone offers any benefits to patients with transabdominal cerclage. Further studies are needed on this topic to conclude.

Intrauterine fetal demise in the case of pregnant women with abdominal cerclage in place is also a challenging situation. A suction curettage can be performed through the cerclage, if necessary, up to 18 weeks. Another option is to remove the stitch via posterior colpotomy. If both options fail, the patient may require a hysterotomy⁽¹⁷⁾.

Planning the delivery in patients with abdominal cerclage is an important subject. There have been described few cases of uterine dehiscence or even rupture of the uterus with labor among this category of patients. Therefore, it is advisable to perform a caesarean delivery before labor begins. The timing is often similar to that of a previous myomectomy. Expert opinion does not have a definite answer on this topic. Some recommend caesarean delivery at 37 weeks, while others prefer deli­very at 39 weeks⁽³⁶⁾.

After delivery, the cerclage does not have to be removed if the patient desires future pregnancies. Ades et al. performed a recent prospective observational study to examine patients who became pregnant for a second or third time after a laparoscopic cerclage. The study found that, when a cerclage was left in place for subsequent pregnancies, neonatal survival rates were as high as 100% in the first pregnancy and 95% in the second⁽⁴⁰⁾. If the patient is determined not to have a future pregnancy or opts for tubal ligation, the stitch can be removed.

Discussion

When transvaginal cerclage placement has failed in the past and a patient has cervical insufficiency, trans­abdominal cerclage (TAC) placement is a very effective way to avoid preterm birth where a transvaginal cerclage would be extremely difficult⁽²³⁾. Patients who have previously delivered before 28 weeks of pregnancy with a transvaginal cerclage in situ should be evaluated for a TAC⁽¹⁾. Although they haven’t been investigated prospectively, minimally invasive techniques for TAC installation seem to be just as successful as open techniques in reducing blood loss and length of hospital stay⁽³⁶⁾. Compared to laparoscopic transabdominal cerclage during pregnancy, laparoscopic TAC before pregnancy produced better reproductive results and was linked to fewer perioperative problems.

Studies showed that, in terms of gestational age at birth and survival, the laparoscopic and open laparotomy abdominal cerclage implantation at intervals or during pregnancy yielded comparable results, according to indirect comparisons. Perioperative care, surgical problems, procedures, and pregnancy-related complications vary slightly⁽⁴⁾. Given that both abdominal cerclage installation techniques have good success rates, we are unable to determine which is better for placing an abdominal cerclage. Future study on transabdominal cerclage will focus on a number of areas. Chronic pelvic pain and morbidity related to recurring surgeries for transabdominal cerclage insertion, caesarean birth, and possibly TAC removal are among the long-term morbidities linked to transabdominal cerclage that should be continuously assessed. To assess the cost-effectiveness of TAC placement, this long-term morbidity should be contrasted with the lower morbidity of fewer failed pregnancies in patients with a transabdominal cerclage^(18-20).

Conclusions

The use of transabdominal cerclage is strongly supported by evidence in women where the anatomy of the cervix would make the placing of a cerclage very difficult or for patients who have a history of failed vaginal cerclage.  As highlighted by different authors, more obstetricians and gynecologists should be offered training in the trans­abdominal cerclage technique to enhance its accessibility for eligible women. This procedure is technically straightforward and can be effectively taught through video, which can be easily shared among clinicians at a low cost. Evidence indicates potential advantages of the laparoscopic approach, such as smaller incisions, less postoperative pain, shorter hospital stays, and quicker recovery times, but both laparoscopic and open approaches are viable options, with complication rates for both types of procedures being rare and comparable. A direct prospective comparison of the two methods has not yet been conducted, thus a large randomized controlled trial and good quality evidence are needed for optimal performance.   

 

CORRESPONDING AUTHOR: Ioana-Emanuela Atanasescu E-mail: ioana-emanuela.atanasescu@rez.umfcd.ro

CONFLICT OF INTEREST: none declared.

FINANCIAL SUPPORT: none declared.

This work is permanently accessible online free of charge and published under the CC-BY.