Comparison of two methods of cervical cerclage by ultrasound cervical measurement

McDonald versus Shirodkar cerclage technique in the prevention of preterm birth: A systematic review and meta-analysis

BACKGROUND

Cervical cerclage has been used for decades to reduce preterm birth. The Shirodkar and McDonald cerclage are the most commonly used techniques with no current consensus on the preferred technique.

OBJECTIVE

To compare the efficacy of the Shirodkar and McDonald cerclage techniques in preventing preterm birth.

SEARCH STRATEGY

Studies were sourced from six electronic databases and reference lists.

SELECTION CRITERIA

Studies including women with a singleton pregnancy, requiring a cervical cerclage, using either the Shirodkar or McDonald technique that ran comparative analyses between the two techniques.

DATA COLLECTION AND ANALYSIS

The primary outcome was preterm birth before 37 weeks, with analyses at 28, 32, 34 and 35 weeks. Secondary data were also collected on neonatal, maternal and obstetric outcomes.

MAIN RESULTS

Seventeen papers were included: 16 were retrospective cohort studies and one was a randomised controlled trial. The Shirodkar technique was significantly less likely to result in preterm birth before 37 weeks than the McDonald technique (relative risk [RR] 0.91, 95% CI 0.85-0.98). This finding was supported by a statistically significant reduction in rates of preterm birth before 35, 34 and 32 weeks, PPROM, difference in cervical length, cerclage to delivery interval, and an increase in birthweight in the Shirodkar group. No difference was seen in preterm birth rates <28 weeks, neonatal mortality, chorioamnionitis, cervical laceration or caesarean section rates. The RR for preterm birth prior to 37 weeks was no longer significant when sensitivity analyses were performed removing studies with a serious risk of bias. However, similar analyses removing studies that utilised adjunctive progesterone strengthened the primary outcome (RR 0.83, 95% CI 0.74-0.93).

CONCLUSION

Shirodkar cerclage reduces the rate of preterm birth prior to 35, 34 and 32 weeks' gestation when compared with McDonald cerclage; however, the overall quality of the studies in this review is low. Further, large, well-designed randomised controlled trials are required to address this important question to optimise care for women who may benefit from cervical cerclage.

Cervical Cerclage: A Review and Rethinking of Current Practice

Importance

Cervical insufficiency (CI) is a serious complication of pregnancy, which can cause preterm birth. Identifying how to most effectively treat CI has the potential to maximize neonatal survival in this population of women.

Objective

To determine whether transabdominal cervical cerclage should be offered as a first-line treatment option in high-risk women.

Evidence Acquisition

An electronic literature search for relevant studies was conducted using keywords (CI, cervical cerclage) on the MEDLINE database.

Results

Although transabdominal cerclage (TAC) is reserved as a second-line treatment option over transvaginal cerclage (TVC), it has some advantages over TVC: a higher placement of the suture at the level of the cervicoisthmic junction; avoidance of placement of foreign material in the vagina, in turn, reducing risk of infection and inflammation, which can propagate preterm labor; and the option to leave the suture in place for future pregnancies. Systematic review evidence offers TAC as a more effective procedure to TVC in reducing preterm birth and maximizing neonatal survival. Although TAC is a slightly more complex procedure compared with TVC, advances in minimally invasive surgery now allow gynecologists to perform this more effective procedure laparoscopically and therefore without the added morbidity of open surgery but with the same if not better outcomes.

Conclusions

Laparoscopic TAC can provide a more effective treatment option for CI without the added burdens of open abdominal surgery.

Relevance

Our article highlights future directions for study in the area of cervical cerclage and refinement of existing practices.

McDonald versus Shirodkar cervical cerclage for prevention of preterm birth: a systematic review and meta-analysis of pregnancy outcomes

OBJECTIVE

To compare pregnancy outcomes of patients undergoing either McDonald or Shirodkar cervical cerclage.

METHODS

PubMed, Web of Science, Scopus, and Google scholar were systematically searched up to June 2020. Inter-study heterogeneity was assessed using Cochrane's Q test and the I² statistic. Data were pooled using the fixed- or random-effects model and expressed as relative risk (RR) or weighted mean difference (WMD) as appropriately.

RESULTS

A total of eight observational studies, reporting data on 724 pregnancies, were included in this meta-analysis. As compared to the Shirodkar cerclage, the pooled findings showed that the gestational age at delivery (WMD = -1.95, 95% CI: -2.89 to -1.01, p < .001; I² = 57.5%) and birth weight (WMD = -355.69, 95% CI: -413.76 to -297.62, p < .001; I² = 28.8%) were significantly lower in McDonald cerclage. The risk of preterm premature rupture of the membranes (PPROM) (RR = 1.76; 95% CI: 1.14 - 2.71; I² = 0.0%) and neonatal intensive care unit (NICU) admission (RR = 1.61; 95% CI: 1.09 - 2.39; I² = 62.1%) were also higher for McDonald group. However, no significant difference was observed between both groups in terms of cesarean delivery and perinatal/neonatal death.

CONCLUSION

McDonald cerclage is associated with a shorter duration of pregnancy, lower mean birth weight and increased risk of PPROM and NICU admission compared to the Shirodkar procedure.

Shirodkar cerclage: Obstetrical and neonatal outcomes in a single-center cohort of 55 cases

BACKGROUND

Cervical insufficiency is thought to be responsible for 10% of preterm deliveries. Shirodkar cerclage is among the available techniques ranging from McDonald's to definitive procedures, however the indications for the prevention of preterm births and mid-trimester miscarriages are still poorly delineated.

OBJECTIVE

To describe the characteristics, obstetrical and neonatal outcomes of pregnancies with Shirodkar cerclage procedures.

METHOD

We performed a descriptive retrospective single-center study, including all patients who had a Shirodkar cerclage between January 1, 2008 and December 31, 2020. The main outcomes measured were delivery at or beyond 24 and 32 weeks of gestations (WG).

RESULTS

55 Shirodkar cerclages were performed over the period studied. 7.3% of patients had a uterine malformation, 9% had a history of cervical conization. 74.5% had history of one or more mid-trimester miscarriages. 63.6% had a history of a failed emergency or prophylactic cerclage. The median gestational age (GA) at cerclage placement was 14 WG. There were 4 deliveries before 24 WG, 8 before 32 WG and 16 before 37 WG. Overall neonatal survival was 48/53 (90.6%). The median GA at delivery was 38 weeks (IQR 35-39), with 70.3% of vaginal deliveries.

CONCLUSION

Shirodkar cerclage was successful in more than 90% of patients, despite their obstetric history. Shirodkar cerclage may be indicated in the event of prior cerclage failure using the McDonald technique or in order to allow for correct stitch placement in very short cervixes. Its advantage over definitive cerclage is to allow for vaginal delivery.

Cerclage Location and Gestational Age at Delivery

Objective  Multiple authors have suggested cerclage position is a determinant of "success." We assessed the interaction between cervical length (CL), cerclage height (cerH), proximal residual length (PRL), gestational age at delivery, and rate of delivery ≤ 34 weeks, in this study. Study Design  Present study is a retrospective cohort study of all cerclages placed at Maimonides Medical Center from 2006 to 2016. Outcomes: gestational age at delivery and delivery before 34 weeks; predictors: PRL, cerH, CL; and indications for cerclage: history (Hx), physical exam (PE), and ultrasound (US) indicated cerclage. A general linear model was used to predict power-transformed age at delivery from cerH, CL, and indication for cerclage. Subanalyses by indication were conducted. Logistic regression was used for delivery ≤ 34 weeks. Results  The cerH by indication did not reach statistical significance ( p  = 0.090). When stratified by indications, the effect of cerH on age at delivery was apparent for Hx (adjusted R ²  = 0.18, p  < 0.001) and PE (adjusted R ²  = 0.43, p  = 0.004) cerclages but not for US cerclages (adjusted R ²  = 0.08, p  = 0.206). Logistic regression predicting delivery ≤ 34 weeks ( n  = 29) produced similar results. Conclusions  For Hx and PE indicated cerclages, the location of the stitch may influence the timing of delivery. Specifically, the higher the cerclage, the more advanced the gestational age at delivery.

McDonald versus Shirodkar cervical cerclage for the prevention of preterm birth: impact of body mass index

Objective: To compare obstetrical outcomes on women undergoing a McDonald or Shirodkar cerclage and to estimate the impact of maternal body mass index (BMI) on these outcomes. Methods: We conducted a retrospective review of the medical records of all women with singleton pregnancies who underwent placement of a McDonald or Shirodkar cerclage at St. Francis Hospital from January 2008 to October 2013. The subjects were categorized based on BMI groups (normal: less than 25 kg/m², overweight: 25-29 kg/m², obese: 30 kg/m² or more). The primary outcome was gestational age at delivery. Statistical analyses included chi-square, Student's t-test, and multivariable regression analysis. Results: Of 95 women, 47 (49.5%) received a Shirodkar, and 48 (50.5%) a McDonald cerclage. 16 women (16.8%) were categorized as normal weight, 35 (36.8%) as overweight, and 44 (46.3%) as obese. Gestational age at delivery differed significantly by group, decreasing with each categorical increase in BMI (normal: 39.0 ± 0.3 weeks; overweight: 36.6 ± 0.7 weeks; obese: 33.0 ± 1.1 weeks; p < .01). Overall, women receiving a Shirodkar cerclage had significantly longer pregnancies than women with a McDonald cerclage (36.7 ± 0.6 weeks versus 33.9 ± 1.0 weeks; p = .02). However, analysis showed a significant interaction between weight status and gestational age at delivery. Obese women had significantly longer pregnancies when they received a Shirodkar cerclage versus a McDonald cerclage (32.6 ± 1.0 weeks versus 28.8 ± 0.9 weeks; p < .01). However, there was no significant difference in gestational age at delivery between women categorized as normal/overweight (Shirodkar: 33.5 ± 0.9 weeks; McDonald: 32.9 ± 0.9 weeks; p = .63). Conclusions: Compared to obese women receiving a McDonald cerclage, obese women receiving a Shirodkar cerclage had significantly longer pregnancies. No significant differences in pregnancy duration were found in normal/overweight women regardless of cerclage technique. Pregnancy duration in obese women receiving a Shirodkar cerclage was similar to the pregnancy duration of normal/overweight women.

Vaginal Cerclage: Preoperative, Intraoperative, and Postoperative Management

The role of the cerclage procedure has expanded from its initial application as treatment or prevention of cervical insufficiency to prevention of recurrent spontaneous preterm birth. Although recent prospective studies have clarified the indications for cerclage, additional prospective studies are needed to help define optimal perioperative management. Herein, we review the current data to provide the clinician with the most evidence-based approach to managing patients who require cerclage.

Comparison of two cervical cerclages for the prevention of preterm birth and neonatal complications

OBJECTIVE

To investigate the outcomes of singleton pregnant women with cervical insufficiency undergoing two different cervical cerclages.

METHODS

This is a retrospective cohort study of women who underwent a history- or ultrasound-indicated cerclage (either Shirodkar or McDonald) at a tertiary referral center from 2002 to 2014. Outcome parameters (delivery age, postoperative cervical length, preterm premature rupture of membranes, preterm delivery rate and neonatal complications) were compared between the two cerclage procedures. Multivariate logistic regression analysis was applied to control for significant variables of preterm birth. Kaplan-Meier survival analysis was used to demonstrate delivery age to percentage of term delivery by cerclage type.

RESULTS

Ninety-four cases were initially included. After excluding cases not meeting the study criteria, 60 pregnancies (Shirodkar 36 and McDonald 24) were recruited for analysis. The mean delivery age in the Shirodkar group was more advanced than that in the McDonald group (37.1 ± 3.3 versus 34.8 ± 4.9 weeks, p = 0.039). There were significantly fewer deliveries <37 gestational weeks in the Shirodkar group than in the McDonald group (30.6% versus 58.3%, p = 0.033) but no significant differences in deliveries <28, 32 and 34 gestational weeks. No significant differences were found in neonatal complications except for respiratory distress syndrome (5.6% in Shirodkar versus 29.2% in McDonald, p = 0.023).

CONCLUSION

In the setting of history-indicated or ultrasound-indicated cerclage, Shirodkar was superior to McDonald in the prevention of late preterm birth and neonatal respiratory distress syndrome.

[Cervical cerclage]

Cervical cerclage aims to strengthen not only the mechanical properties of the cervix, but also its immunological and anti-infectious functions. The demonstration of a strong interrelation between cervical insufficiency as well as decreased cervical length at endo-vaginal ultrasonography and infection has changed the indications cerclage. Actually we can distinguish three indications for cerclage: prophylactic, for obstetrical history; therapeutic, for shortened cervical length at ultrasonography in patients at risk and; emergency cerclage in case of threatening cervix at physical examination. The McDonald's technique is the most recommended. In case of failure, it is proposed to realize cerclage at a higher level on the cervix either by vaginal or abdominal route.

Trachelorraphy in cases of recurrent second trimester loss and prior failed vaginal cerclage

OBJECTIVE

To evaluate the obstetric results of trachelorraphy in the prevention of recurrent second trimester loss in cases of prior failed vaginal cerclage.

STUDY DESIGN

Data were collected retrospectively and prospectively from medical records. The analysis examined data for 18 women who underwent trachelorraphy between 2004 and 2013 at a tertiary referral unit in France. All patients in this high-risk population had a history of two or more second trimester losses, or one second trimester loss and one preterm labour, and at least one prior failed transvaginal cerclage. The main outcome measures were: livebirth rate; rate of second trimester loss; and surgical complications.

RESULTS

Twenty pregnancies were conceived in 16 patients following trachelorraphy. Three patients experienced two pregnancies. Among the 20 pregnancies, there was one case of fetal loss in the first trimester; this pregnancy was excluded from the analysis. Of the remaining 19 pregnancies, there were nine (47%) term deliveries (after 37 weeks of gestation), seven (32%) preterm deliveries and three (16%) second trimester losses. The overall fetal survival rate was 84%. Surgical outcomes were excellent, with no complications.

CONCLUSION

Trachelorraphy is a safe, reproducible, easy-to-learn procedure for the prevention of recurrent second trimester loss in cases of prior failed vaginal cerclage. The procedure has encouraging and favourable perinatal outcomes in patients with a poor obstetric history.

Transvaginal cervical cerclage: evidence for perioperative management strategies

The objective was to review the evidence supporting various perioperative technical and management strategies for transvaginal cervical cerclage. We performed MEDLINE, PubMed, EMBASE, and COCHRANE searches with the terms, cerclage, cervical cerclage, cervical insufficiency, and randomized trials, plus each technical aspect (eg, suture, amniocentesis, etc) considered. The search spanned 1966 through September 2012 and was not restricted by language. Each retrieved manuscript was carefully evaluated, and any pertinent references from the reports were also obtained and reviewed. All randomized trials covering surgical and selected perioperative, nonsurgical aspects of cerclage were included in the review. The evidence was assessed separately for history-, ultrasound-, and physical examination-indicated cerclage. Evidence levels according to the new method outlined by the US Preventive Services Task Force were assigned based on the evidence. There are no grade A high-certainty recommendations regarding technical aspects of transvaginal cervical cerclage. Grade B moderate-certainty recommendations include performing a fetal ultrasound before cerclage to ensure fetal viability, confirm gestational age, and assess fetal anatomy to rule out clinically significant structural abnormalities; administering spinal, and not general, anesthesia; performing a McDonald cerclage, with 1 stitch, placed as high as possible; and outpatient setting. Unfortunately, no other recommendations can be made regarding the other technical aspects of cerclage.

Comparison of 2 stitches vs 1 stitch for transvaginal cervical cerclage for preterm birth prevention

OBJECTIVE

The objective of the study was to compare the efficacy and outcomes of 2 vs 1 stitch at the time of cervical cerclage placement for preterm birth prevention.

STUDY DESIGN

This was a retrospective cohort study of women with singleton gestation undergoing history- or ultrasound-indicated transvaginal cervical cerclage prior to 24 weeks. The primary outcome was delivery at less than 37 weeks. The secondary outcomes included gestational age at delivery at less than 35, less than 34, less than 32, less than 28, and less than 24 weeks, perioperative details at the time of cerclage placement and removal, and maternal and neonatal outcomes. Comparison was made between patients with 2 vs 1 stitch at the time of cerclage placement. History- and ultrasound-indicated cerclages were analyzed separately.

RESULTS

Four hundred forty-four patients met inclusion criteria, 237 being history indicated (2 stitches, n = 86, 1 stitch, n = 151), and 207 ultrasound indicated (2 stitches, n = 117, 1 stitch, n = 90). Gestational age at delivery at less than 37 weeks was not significantly different between the 2 groups for both history- and ultrasound-indicated cerclage, even after adjusting for demographic differences and suture type (39% vs 35%; adjusted odds ratio, 1.38; 95% confidence interval, 0.64-3.01; and 44% vs 49%; adjusted odds ratio, 0.66; 95% confidence interval, 0.27-1.61, respectively).

CONCLUSION

Two stitches at the time of cerclage do not appear to improve pregnancy outcome either in the history- or the ultrasound-indicated procedures, compared with 1 stitch.

Reducing stillbirths: prevention and management of medical disorders and infections during pregnancy

BACKGROUND

An estimated two-thirds of the world's 3.2 million stillbirths occur antenatally, prior to labour, and are often overlooked in policy and programs. Poorly recognised, untreated or inadequately treated maternal infections such as syphilis and malaria, and maternal conditions including hypertensive disorders, are known risk factors for stillbirth.

METHODS

We undertook a systematic review of the evidence for 16 antenatal interventions with the potential to prevent stillbirths. We searched a range of sources including PubMed and the Cochrane Library. For interventions with prior Cochrane reviews, we conducted additional meta-analyses including eligible newer randomised controlled trials following the Cochrane protocol. We focused on interventions deliverable at the community level in low-/middle-income countries, where the burden of stillbirths is greatest.

RESULTS

Few of the studies we included reported stillbirth as an outcome; most that did were underpowered to assess this outcome. While Cochrane reviews or meta-analyses were available for many interventions, few focused on stillbirth or perinatal mortality as outcomes, and evidence was frequently conflicting. Several interventions showed clear evidence of impact on stillbirths, including heparin therapy for certain maternal indications; syphilis screening and treatment; and insecticide-treated bed nets for prevention of malaria. Other interventions, such as management of obstetric intrahepatic cholestasis, maternal anti-helminthic treatment, and intermittent preventive treatment of malaria, showed promising impact on stillbirth rates but require confirmatory studies. Several interventions reduced known risk factors for stillbirth (e.g., anti-hypertensive drugs for chronic hypertension), yet failed to show statistically significant impact on stillbirth or perinatal mortality rates. Periodontal disease emerged as a clear risk factor for stillbirth but no interventions have reduced stillbirth rates.

CONCLUSION

Evidence for some newly recognised risk factors for stillbirth, including periodontal disease, suggests the need for large, appropriately designed randomised trials to test whether intervention can minimise these risks and prevent stillbirths. Existing evidence strongly supports infection control measures, including syphilis screening and treatment and malaria prophylaxis in endemic areas, for preventing antepartum stillbirths. These interventions should be incorporated into antenatal care programs based on attributable risks and burden of disease.

Demographics and outcome of elective cerclage in a multi-ethnic London district general hospital

Elective cerclage is a rare procedure, but is reported to be relatively more common in developing countries. This variation in rate may be reflected in a multi-ethnic population as seen in London. Our study analysed the epidemiology and rate of elective cerclage performed in a London district general hospital. Factors contributing to the outcome of the procedures were also reviewed. A total of 41 elective cerclages were performed in the hospital between 2000 and 2007. Data from these were collected retrospectively, including maternal history, operative details, and gestational age at delivery. Fisher's exact test was used for statistical analysis. Of the 41 cases, 19 pregnancies were carried to term (>or=37 weeks' gestation), nine were pre-term (24-36 weeks' gestation) and seven miscarried (<24 weeks' gestation); six cases had not yet delivered. All of the patients were immigrants from developing countries but ethnicity did not affect the operative outcome (p = 0.89, Fisher's exact). The other factors studied were also noted to have no significant impact on success. These included cervical length at insertion (p = 1.00, Fisher's exact), type of suture (p = 0.90, Fisher's exact) and average gestation at insertion (p = 0.20, Fisher's exact). In conclusion, all patients requiring intervention in this study originated from developing countries. This is a disproportionately high figure relative to the demographic breakdown of the study population. Such a finding may be due to geographical variation of risk factors for cervical incompetence but may also be influenced by observer bias. Additional studies are needed to further investigate the influence of ethnicity on the rate of elective cerclage. None of the variables analysed in this study significantly affected the outcome of the procedure.

Management of painless mid-trimester cervical dilatation: Prophylactic vs emergency placement of cervical cerclage

Women with recurrent painless mid-trimester miscarriages are often diagnosed with cervical insufficiency. Presenting symptoms typically include vaginal pressure and minimal bleeding; when the cervix is examined, advanced dilatation is usually detected. Labour is short and the premature fetus is born alive. Women with this history were traditionally considered candidates for the placement of cervical cerclage. Recently, this practice has been called into question. Rather than routine placement of prophylactic cervical cerclage at 12 - 14 weeks, many patients are followed expectantly with serial sonographic assessments of cervical length. The goal of this update is to review the literature regarding management options of mid-trimester cervical dilatation.

Cervical cerclage in the prevention of preterm birth

Cervical cerclage has been used in the management of cervical insufficiency for several decades, yet the indications are uncertain and benefits marginal. It remains a controversial intervention. The diagnosis of cervical insufficiency is traditionally based on a history of recurrent second trimester miscarriages, or very preterm delivery whereby the cervix is unable to retain the pregnancy until term. Cervical cerclage has been the subject of many observational and randomised controlled trials. This article reviews the literature regarding the effectiveness of elective or emergency transvaginal cerclage and transabdominal cerclage.

PREMATURE CERVICAL CHANGE AND THE USE OF CERVICAL CERCLAGE

Preterm birth and its subsequent consequences continue to be a major challenge worldwide. In the United States in 2004, 12.5% of infants were born preterm, making the annual societal economic burden associated with preterm birth in excess of $26.2 billion (and this is a modest estimate). Spontaneous preterm birth accounts for about 75% of all preterm births; however, at earlier gestations iatrogenic preterm birth accounts for a greater proportion of all preterm births; at 27–28 weeks 50% are iatrogenic. The proportion of babies transferred to the neonatal unit is more than 90% for those born before 33 completed weeks of gestation compared with 31% at 36 weeks; delivery between 33 completed weeks and 36 completed weeks has a relatively low morbidity and mortality. Nonetheless, 1 in 3 children born preterm but beyond 32 weeks have educational and behavioural problems at the age of 7, with 1 in 4 children born between 32 and 35 weeks requiring support from non-teaching assistants at school. Although more than 40% of babies at 35 completed weeks show signs of maturity, some still need ventilation at 38 completed weeks. Almost one-fifth of all infants born at less than 32 weeks gestation do not survive the first year of life.

The cervix and prematurity: aetiology, prediction and prevention

Preventing preterm delivery remains a major challenge for the 21st century. The cervix plays a fundamental role in supporting a pregnancy and preventing ascending infection from the lower genital tract. Infection is associated with early preterm delivery in about half of cases. Whatever the aetiology of preterm delivery, dilation of the cervix is a common endpoint, and transvaginal scanning of the cervix now provides a good predictor of early preterm delivery in both high- and low-risk women. Changes in the cervix are related to the detection of fetal fibronectin in the vagina, which is also an accurate predictor of delivery. However, the role of intervention in at-risk women is unclear. Elective cerclage is only effective in a minority of women, and the evidence to support its use is limited. It is currently being evaluated whether indicated cerclage, dictated by ultrasound findings, is beneficial.