Cervical cerclage for prevention of preterm birth and adverse perinatal outcome in twin pregnancies with short cervical length or cervical dilatation: A systematic review and meta-analysis

Interventions for women with premature cervical dilatation and exposed fetal membranes to prevent pregnancy loss and preterm birth - A systematic review and meta-analysis

INTRODUCTION

The management of women with premature cervical dilatation and exposed unruptured fetal membranes remains uncertain and controversial. Treatment options may include expectant management or emergency cervical cerclage (ECC). Little is known regarding the effectiveness of individual interventions, or additional therapies. This systematic review aims to summarise all existing evidence to improve understanding of the treatment options and pregnancy outcomes for women presenting with premature cervical dilatation.

METHODS

Databases were searched using a prospective protocol (CRD42021286275). Studies were eligible for inclusion across five distinct comparison groups if they included women with premature cervical dilatation and reported clinical outcomes. Primary outcome was pregnancy loss (miscarriage, stillbirth, neonatal death and termination of pregnancy). Planned subgroups included singletons and twins, and low-cervical or high-cervical suture. Pairwise random effects meta-analysis calculated in RevMan5.4, single arm random effects proportional meta-analysis calculated using RevMan and R studio. Risk of bias was assessed using Cochrane Risk of Bias tool and Joanna Briggs Institute checklists.

RESULTS

6781 abstracts were screened, and 177 (four randomised controlled trials) studies included in the five analysis groups. Women receiving ECC were significantly less likely to experience pregnancy loss (combined RR 0.48 95 %CI 0.39-0.59 singleton RR 0.48 95 %CI 0.34-0.67 twin only RR 0.39 95 %CI 0.26-0.58) compared to expectant management. Adjuvant amnioreduction with ECC was not found to reduce pregnancy loss (RR 1.12 (95 % CI 0.73-1.72) or any other outcomes compared to ECC without amnioreduction. Women were significantly more likely to experience pregnancy loss (RR3.85 95 %CI 3.13-4.74) after ECC compared to planned cerclage. The probability of intra-operative rupture of membranes at ECC insertion was 3.3 % (95 %CI 1.8-5.1) and the probability of an ECC attempt being abandoned was 2.6 % (95 %CI 1.1-4.6 %).

DISCUSSION

ECC appears to reduce the risk of pregnancy loss for both singletons and twins although the overall quality of evidence is poor. It is important that women are counselled regarding the outcomes following cerclage according to indication. Pregnancy complications are common after ECC although the rates of intra-operative complications are lower than may be anticipated. Randomised trials remain imperative for understanding the role of ECC and adjunctive treatments in preventing pregnancy loss in this condition.

Cervical cerclage: An evolving evidence base

Cervical cerclage is an established intervention for the management of pregnancies at high risk of preterm birth. Although studies exist to support its use in certain situations, particularly in singleton pregnancies, many questions such as adjunct therapies and efficacy in specific subgroups of high-risk women have not been fully elucidated. This review will assess the current evidence as well as areas where there is currently a paucity of data and an urgent requirement for further research.

Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation: the TWIN Cerclage studies

INTRODUCTION

Twin pregnancies have a high risk of extreme preterm birth (PTB) at less than 28 weeks of gestation, which is associated with increased risk of neonatal morbidity and mortality. Currently there is a lack of effective treatments for women with a twin pregnancy and a short cervix or cervical dilatation. A possible effective surgical method to reduce extreme PTB in twin pregnancies with an asymptomatic short cervix or dilatation at midpregnancy is the placement of a vaginal cerclage.

METHODS AND ANALYSIS

We designed two multicentre randomised trials involving eight hospitals in the Netherlands (sites in other countries may be added at a later date). Women older than 16 years with a twin pregnancy at <24 weeks of gestation and an asymptomatic short cervix of ≤25 mm or cervical dilatation will be randomly allocated (1:1) to both trials on vaginal cerclage and standard treatment according to the current Dutch Society of Obstetrics and Gynaecology guideline (no cerclage). Permuted blocks sized 2 and 4 will be used to minimise the risk of disbalance. The primary outcome measure is PTB of <28 weeks. Analyses will be by intention to treat. The first trial is to demonstrate a risk reduction from 25% to 10% in the short cervix group, for which 194 patients need to be recruited. The second trial is to demonstrate a risk reduction from 80% to 35% in the dilatation group and will recruit 44 women. A cost-effectiveness analysis will be performed from a societal perspective.

ETHICS AND DISSEMINATION

This study has been approved by the Research Ethics Committees in the Netherlands on 3/30/2023. Participants will be required to sign an informed consent form. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT05968794.

Randomized controlled trials: not always the "gold standard" for evidence in obstetrics and gynecology

Randomized controlled trials are considered the "gold standard" for therapeutic interventions, and it is not uncommon for sweeping changes in medical practice to follow positive results from such trials. However, randomized controlled trials are not without their limitations. Physicians frequently view randomized controlled trials as infallible, whereas they tend to dismiss evidence derived from sources other than randomized controlled trials as less credible or reliable. In several situations in obstetrics and gynecology, there are no randomized controlled trials to help guide the clinician. In these circumstances, it is important to evaluate the entire body of evidence including observational studies, rather than dismiss interventions altogether simply because no randomized controlled trials exist. Randomized controlled trials and observational studies should be viewed as complementary rather than at odds with each other. Some reversals in widely adopted clinical practice have recently been implemented following subsequent studies that contradicted the outcomes of major randomized controlled trials. The most notable of these was the withdrawal from the market of 17-hydroxyprogesterone caproate for preterm birth prevention. Such reversals could potentially have been averted if the inherent limitations of randomized controlled trials were carefully considered before implementing these universal practice changes. This Clinical Opinion underscores the limitations of an exclusive reliance on randomized controlled trials while disregarding other evidence in determining how best to care for patients. Solutions are proposed that advocate that clinicians adopt a more balanced perspective that considers the entirety of the available medical evidence and the individual patient characteristics, needs, and wishes.

Development and validation of a prediction model on spontaneous preterm birth in twin pregnancy: a retrospective cohort study

BACKGROUND

This study was conducted to develop and validate an individualized prediction model for spontaneous preterm birth (sPTB) in twin pregnancies.

METHODS

This a retrospective cohort study included 3845 patients who gave birth at the Chongqing Maternal and Child Health Hospital from January 2017 to December 2022. Both univariable and multivariable logistic regression analyses were performed to find factors associated with sPTB. The associations were estimated using the odds ratio (OR) and the 95% confidence interval (CI). Model performance was estimated using sensitivity, specificity, accuracy, area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA).

RESULTS

A total of 1313 and 564 cases were included in the training and testing sets, respectively. In the training set, univariate and multivariate logistic regression analysis indicated that age ≥ 35 years (OR, 2.28; 95% CI 1.67-3.13), pre-pregnancy underweight (OR, 2.36; 95% CI 1.60-3.47), pre-pregnancy overweight (OR, 1.67; 95% CI 1.09-2.56), and obesity (OR, 10.45; 95% CI, 3.91-27.87), nulliparity (OR, 0.58; 95% CI 0.41-0.82), pre-pregnancy diabetes (OR, 5.81; 95% CI 3.24-10.39), pre-pregnancy hypertension (OR, 2.79; 95% CI 1.44-5.41), and cervical incompetence (OR, 5.12; 95% CI 3.08-8.48) are independent risk factors for sPTB in twin pregnancies. The AUC of the training and validation set was 0.71 (95% CI 0.68-0.74) and 0.68 (95% CI 0.64-0.73), respectively. And then we integrated those risk factors to construct the nomogram.

CONCLUSIONS

The nomogram developed for predicting the risk of sPTB in pregnant women with twins demonstrated good performance. The prediction nomogram serves as a practical tool by including all necessary predictors that are readily accessible to practitioners.