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.

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.