Perioperative complications of a transvaginal cervical cerclage in singleton pregnancies: a systematic review and meta-analysis.

OBJECTIVE: Given that many studies report on a limited spectrum of adverse events of transvaginal cervical cerclage for preventing preterm birth, but are not powered to draw conclusions about its safety, the objective of this study was to conduct a systematic review with pooled risk analyses of perioperative complications and compare characteristics on the basis of indication for cerclage in singleton pregnancies. DATA SOURCES: Ovid MEDLINE, Ovid Embase, Web of Science, the Cochrane Central Register of Controlled Trials (CENTRAL), and the prospective trial registers ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform were searched from inception to April 2020. STUDY ELIGIBILITY CRITERIA: All randomized controlled trials and both retrospective and prospective observational cohort studies reporting about complications in history-indicated cerclage, ultrasound-indicated cerclage, or physical examination-indicated cerclage were eligible. Studies were included if they contained original data on the occurrence of adverse events during surgery or within 24 hours after surgery. METHODS: The Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa scale for cohort and case-control studies were used for the critical appraisal. The pooled risk assessment was conducted using meta and metafor packages in R (studio), version 4.0.3. RESULTS: The search yielded 2328 potential studies; 3 randomized controlled trials, 3 prospective, and 38 retrospective cohort studies were included in the final analysis. Of the 4511 women with singleton gestations, 1561 (34.6%) underwent history-indicated cerclage, 1348 (29.9%) underwent ultrasound-indicated cerclage, and 1549 (33.3%) underwent physical examination-indicated cerclage. Most perioperative complications occurred in physical examination-indicated cerclage, especially hemorrhage (2.3%; 95% confidence interval, 0.0-7.6) and preterm premature rupture of membranes (2.5%; 95% confidence interval, 0.91-4.5). The fewest complications occurred in history-indicated cerclage, varying from 0.0% of preterm premature rupture of membranes (95% confidence interval, 0.0-1.7) to 0.9% of hemorrhage (95% confidence interval, 0.0-7.9). In ultrasound-indicated cerclage, the most common complication was hemorrhage (1.4%; 95% confidence interval, 0.0-4.1), followed by lacerations (0.6%; 95% confidence interval, 0.0-3.1) and preterm premature rupture of membranes (0.3%; 95% confidence interval, 0.0-0.8). CONCLUSION: The highest risk of perioperative complications was observed in physical examination-indicated cerclage in comparison with ultrasound- and history-indicated cerclage. However, the occurrence of complications is poorly documented in the published literature, as is the timing of the complications (ie, perioperative or later in pregnancy). There is an urgent need for uniform complication reporting policy in both cohort studies and randomized controlled trials on cerclage.

The impact of cut-off values on the prevalence of short cervical length in pregnancy.

BACKGROUND: A prior study suggested that implementing a cut-off value of ≤30 mm for a short cervical length (CL) could potentially introduce selection bias and alter the distribution of CL measurements. As such, the objective of this study is to evaluate how CL distribution and incidence of short CL are affected when using different cut-off values for a short CL. STUDY DESIGN: This is a secondary analysis of the Quadruple P (QP) Screening study; a prospective cohort study that included low-risk patients with singleton pregnancies undergoing fetal anomaly scan at 18-22 weeks of gestation, including a CL measurement. Patients with a short cervix, defined as ≤35 mm, were subsequently counseled for the QP trial; a randomized controlled trial (RCT) comparing progesterone to cervical pessary for the prevention of preterm birth. If participation to the RCT was refused, patients with a CL ≤25 mm were advised to use progestogen. The primary objective of this current study was to assess the normal distribution of CL across the entire cohort and to assess the incidence of short CL when using the cut-off values of ≤35 and ≤25 mm. Normal distributions for CL were simulated based on mean and standard deviation(SD) of the original data. The Kolmogorov-Smirnov test was used to evaluate the distribution of the CL measurements. Moreover, to evaluate the motives behind ultrasound measurements around the cut-off value, sonographers were asked to fill out a qualitative questionnaire. RESULTS: The total cohort included 19.171 eligible participants who underwent CL measurement, with a mean CL of 43.9 mm (±8.1 SD). The distribution of all CL observed measurements deviated significantly from the normal distribution (p < 0.001). A total of 1.852 (9.7%) patients had short CL ≤35 mm, which was significantly lower than expected when compared to the simulated normal distribution (n = 2.661, 13.9%; p < 0.001). The incidence of short CL ≤25 mm in our cohort statistically differed from the simulated normal distribution (238, 1.2% vs 177, 0.9%; p=0.003). When comparing our data to the simulated normal distribution, the difference in distributions is most pronounced when examining the difference between 35 and 36 mm. Results of the questionnaire reveal sonographers claimed not to be influenced by a cut-off value for study participation or progesterone treatment. CONCLUSION: This study demonstrates that using any cut-off value for a short CL influences the incidence and distribution of CL. When using a cut-off value of ≤35 mm for study inclusion, the incidence of measurements of a short CL is lower than the anticipated incidence compared to a normal distribution. However, when using a cut-off value of ≤25 mm for progesterone treatment, the frequency of CL measurements is higher than expected below this threshold compared to a normal distribution. This study highlights the risk of introducing selection bias, most likely unintentionally, when cut-off values for short CL are used, regardless of the specific value chosen. Therefore healthcare providers should measure the CL with caution if essential decisions depend on a specific cut-off value.

Cervical pessary versus vaginal progesterone in women with a singleton pregnancy, a short cervix, and no history of spontaneous preterm birth at less than 34 weeks' gestation: open label, multicentre, randomised, controlled trial.

OBJECTIVE: To compare the effectiveness of cervical pessary and vaginal progesterone in the prevention of adverse perinatal outcomes and preterm birth in pregnant women of singletons with no prior spontaneous preterm birth at less than 34 weeks' gestation and who have a short cervix of 35 mm or less. DESIGN: Open label, multicentre, randomised, controlled trial. SETTING: 20 hospitals and five obstetric ultrasound practices in the Netherlands. PARTICIPANTS: Women with a healthy singleton pregnancy and an asymptomatic short cervix of 35 mm or less between 18 and 22 weeks' gestation were eligible. Exclusion criteria were prior spontaneous preterm birth at less than 34 weeks, a cerclage in situ, maternal age of younger than 18 years, major congenital abnormalities, prior participation in this trial, vaginal blood loss, contractions, cervical length of less than 2 mm or cervical dilatation of 3 cm or more. Sample size was set at 628 participants. INTERVENTIONS: 1:1 randomisation to an Arabin cervical pessary or vaginal progesterone 200 mg daily up to 36 weeks' of gestation or earlier in case of ruptured membranes, signs of infection, or preterm labour besides routine obstetric care. MAIN OUTCOME MEASURES: Primary outcome was a composite adverse perinatal outcome. Secondary outcomes were rates of (spontaneous) preterm birth at less than 28, 32, 34, and 37 weeks. A predefined subgroup analysis was planned for cervical length of 25 mm or less. RESULTS: From 1 July 2014 to 31 March 2022, 635 participants were randomly assigned to pessary (n=315) or to progesterone (n=320). 612 were included in the intention to treat analysis. The composite adverse perinatal outcome occurred in 19 (6%) of 303 participants with a pessary versus 17 (6%) of 309 in the progesterone group (crude relative risk 1.1 (95% confidence interval (CI) 0.60 to 2.2)). The rates of spontaneous preterm birth were not significantly different between groups. In the subgroup of cervical length of 25 mm or less, spontaneous preterm birth at less than 28 weeks occurred more often after pessary than after progesterone (10/62 (16%) v 3/69 (4%), relative risk 3.7 (95% CI 1.1 to 12.9)) and adverse perinatal outcomes seemed more frequent in the pessary group (15/62 (24%) v 8/69 (12%), relative risk 2.1 (0.95 to 4.6)). CONCLUSIONS: In women with a singleton pregnancy with no prior spontaneous preterm birth at less than 34 weeks' gestation and with a midtrimester short cervix of 35 mm or less, pessary is not better than vaginal progesterone. In the subgroup of a cervical length of 25 mm or less, a pessary seemed less effective in preventing adverse outcomes. Overall, for women with single baby pregnancies, a short cervix, and no prior spontaneous preterm birth less than 34 weeks' gestation, superiority of a cervical pessary compared with vaginal progesterone to prevent preterm birth and consecutive adverse outcomes could not be proven. TRIAL REGISTRATION: International Clinical Trial Registry Platform (ICTRP, EUCTR2013-002884-24-NL).

Few randomized trials in preterm birth prevention meet predefined usefulness criteria.

OBJECTIVES: We operationalized a research usefulness tool identified through literature searches and consensus and examined if randomized controlled trials (RCTs) addressing preterm birth prevention met predefined criteria for usefulness. STUDY DESIGN AND SETTING: The usefulness tool included eight criteria combining 13 items. RCTs were evaluated for compliance with each item by multiple assessors (reviewer agreement 95-98%). Proportions of compliances with 95% confidence interval (CI) were calculated and change over time was assessed using â‰§ 2010 as a cutoff. RESULTS: Among 347 selected RCTs, published within 56 preterm birth Cochrane reviews, only 36 (10%, 95% CI = 7-14%) met more than half of the usefulness criteria. Compared to trials before 2010, recent trials used composite or surrogate (less informative) outcomes more often (13% vs. 25%, relative risk 1.91, 95% CI = 1.21-3.00). Only 16 trials reflected real practice (pragmatism) in design (5%, 95% CI = 3-7%), with no improvements over time. No trials reported involvement of mothers to reflect patients' research priorities and outcomes selection. Recent trials were more transparent. CONCLUSION: Few preterm birth prevention RCTs met more than half of the usefulness criteria but most of usefulness criteria are improving after 2010. Use of informative outcomes, patient centeredness, pragmatism and transparency should be key targets for future research planning.

Risk of preterm birth for placenta previa or low-lying placenta and possible preventive interventions: A systematic review and meta-analysis.

Objective: To investigate the risk of preterm birth in women with a placenta previa or a low-lying placenta for different cut-offs of gestational age and to evaluate preventive interventions. Search and methods: MEDLINE, EMBASE, CENTRAL, Web of Science, WHO-ICTRP and clinicaltrials.gov were searched until December 2021. Randomized controlled trials, cohort studies and case-control studies assessing preterm birth in women with placenta previa or low-lying placenta with a placental edge within 2 cm of the internal os in the second or third trimester were eligible for inclusion. Pooled proportions and odds ratios for the risk of preterm birth before 37, 34, 32 and 28 weeks of gestation were calculated. Additionally, the results of the evaluation of preventive interventions for preterm birth in these women are described. Results: In total, 34 studies were included, 24 reporting on preterm birth and 9 on preventive interventions. The pooled proportions were 46% (95% CI [39 - 53%]), 17% (95% CI [11 - 25%]), 10% (95% CI [7 - 13%]) and 2% (95% CI [1 - 3%]), regarding preterm birth <37, <34, <32 and <28 weeks in women with placenta previa. For low-lying placentas the risk of preterm birth was 30% (95% CI [19 - 43%]) and 1% (95% CI [0 - 6%]) before 37 and 34 weeks, respectively. Women with a placenta previa were more likely to have a preterm birth compared to women with a low-lying placenta or women without a placenta previa for all gestational ages. The studies about preventive interventions all showed potential prolongation of pregnancy with the use of intramuscular progesterone, intramuscular progesterone + cerclage or pessary. Conclusions: Both women with a placenta previa and a low-lying placenta have an increased risk of preterm birth. This increased risk is consistent across all severities of preterm birth between 28-37 weeks of gestation. Women with placenta previa have a higher risk of preterm birth than women with a low-lying placenta have. Cervical cerclage, pessary and intramuscular progesterone all might have benefit for both women with placenta previa and low-lying placenta, but data in this population are lacking and inconsistent, so that solid conclusions about their effectiveness cannot be drawn. Systematic review registration: PROSPERO https://www.crd.york.ac.uk/prospero/, identifier CRD42019123675.

Pessary or progesterone to prevent preterm birth in women with short cervical length: protocol of the 4-6 year follow-up of a randomised controlled trial (Quadruple-P).

INTRODUCTION: Vaginal progesterone and a cervical pessary are both interventions that are investigated for the prevention of preterm birth (PTB). Thus far, beneficial or harmful effects of these interventions on long-term child health and development are described, but evidence is not robust enough to draw firm conclusions. With this follow-up study, we intent to investigate if progesterone or a pessary is superior for the prevention of PTB considering the child's health at 4-6 years of corrected age. METHODS AND ANALYSIS: This study is a follow-up study of the Quadruple-P trial; a multicentre, randomised clinical trial (NL42926.018.13, Eudractnumber 2013-002884-24) which randomises women with an asymptomatic midtrimester short cervix to daily progesterone or a pessary for the prevention of PTB. All children born to mothers who participated in the Quadruple-P study (n=628 singletons and n=332 multiples) will be eligible for follow-up at 4-6 years of corrected age. Children will be assessed using parental questionnaires. Main outcomes are child (neuro)development and behaviour. Other outcomes include child mortality, growth and general health. A composite of adverse child outcomes will be compared between the progesterone and pessary groups reporting OR and the corresponding 95% CI. Analyses will be performed separately for singletons and multiples and using the intention-to-treat approach. ETHICS AND DISSEMINATION: The Medical Research Ethics Committee from Amsterdam UMC confirmed that de Medical Research Involving Human Subjects Act (WMO) did not apply to our study (W20_481 #20.531). Results will be published in a peer-reviewed journal and shared with stakeholders and participants. This protocol is published before analysis of the results. TRIAL REGISTRATION NUMBER: Dutch Trial Register (NL9646).