Background Preterm birth (PTB) is the leading cause of death in children under five years. Spontaneous preterm birth (SPTB) is the major cause of preterm delivery. The key risk factors for SPTB are women who have a short cervix and women who have had previous preterm birth. Cervical cerclage has been used for several decades and has shown to decrease rates of preterm birth. The most commonly used cerclage techniques were described by Shirodkar and McDonald, with no current consensus on the preferred technique. The objective of this review is to determine and compare the effectiveness of both techniques. Methods Studies will be sourced from six electronic databases, as well as from experts in the field, reference lists, and grey literature. Eligible studies will include pregnant women, with a singleton or twin pregnancy, requiring a cervical cerclage, using either the Shirodkar or McDonald technique and run comparative analyses between the two techniques. Randomized control trials (RCT)s, non-randomized control trials, and cohort studies will be eligible. Two independent reviewers will conduct study screening at abstract and full-text level, data extraction and risk of bias assessment. Discrepancies will be resolved by a consensus third reviewer if required. Fixed-effects or random-effects models will be used where appropriate to synthesize results. Alternative synthesis methods will be investigated in instances where a meta-analysis is not appropriate, such as summarizing effect estimates, combining P values, vote counting based on direction of effect, or synthesis in narrative form. Discussion This review will synthesize the evidence on both the Shirodkar and McDonald cerclage method, and will help clinicians and health services to determine and deliver best practice antenatal care that has the potential to make an impact on preterm birth. Systematic review registration PROSPERO on 25 of May, 2020 with registration number CRD42020177386

Background Preterm birth (PTB) is estimated to affect 14.9 million babies globally every year. Global rates of PTB continue to increase from 9.8 to 10.6% over a 15-year period from 2000 to 2014. Vaginal progesterone is commonly used by clinicians as a prevention strategy, with recent evidence affirming the benefit of vaginal (micronised) progesterone to prevent PTB in women with a shortened cervix (< 25 mm). Given the low incidence of a short cervix at mid-gestation in high-risk populations further evidence is required. The objective of this review is to determine if vaginal progesterone reduces spontaneous preterm birth (sPTB) before 37 weeks in asymptomatic high-risk women with a singleton pregnancy with a normal mid-gestation cervical length. Methods Studies will be sourced from MEDLINE, Embase and Cochrane Register of Trials (CENTRAL) from their inception onwards with the search terms ‘progesterone’ and ‘preterm birth’. Studies will be screened and included if they assess vaginal progesterone compared to placebo in women with a normal cervical length. The primary outcome will be sPTB < 37 weeks, with secondary outcomes of sPTB < 34 weeks. Two independent reviewers will conduct study screening at abstract and full text level, data extraction and risk of bias assessment with disagreements resolved by an experienced researcher. The Mantel-Haenszel statistical method and random effects analysis model will be used to produce treatment effect odds ratios and corresponding 95% confidence intervals. Discussion This review will assess the current body of evidence and provide clarity regarding the potential benefits and best practice of use of vaginal progesterone in asymptomatic women with high-risk singleton pregnancies and normal cervical length. Trial registration PROSPERO CRD42020152051

IntroductionPreterm birth (PTB) is the leading cause of death in children under 5 years. Preventive therapies targeted towards women with risk factors such as a prior PTB or a short cervix reduce the rate of PTB. Cervical cerclage, vaginal progesterone and a combination of the two have been used with no consensus as to whether combined treatment is more effective than any single treatment alone. The objective of this review is to determine the efficacy of combined treatment compared with cerclage alone and combined treatment compared with progesterone alone.Methods and analysisStudies will be sourced from the electronic databases Medline (Ovid), EMBASE (Ovid), PsycINFO (Ovid), Scopus, CINAHL (EBSCOhost) and Cochrane Library (Wiley) and reference lists. We will not exclude any papers due to publication date. Randomised control trials (RCTs), non-RCTs and cohort studies assessing single therapy (either progesterone or cerclage) versus combined therapy in women with a singleton pregnancy will be included. Two independent reviewers will conduct study screening (at abstract and full-text level), data extraction and risk of bias assessment with disagreements resolved by an experienced researcher. Random or fixed effects models will be used depending on data heterogeneity and data will be presented as risk ratio for dichotomous data or mean difference for continuous data with a CI of 95% used for all outcomes.Ethics and disseminationNot applicable due to nature of the study type.PROSPERO registration numberCRD42020195975.

Background: Preterm birth (PTB) is estimated to affect 14.9 million babies globally every year. Global rates of PTB continue to increase from 9.8% to 10.6% over a 15-year period from 2000 to 2014. Vaginal progesterone is commonly used by clinicians as a prevention strategy, with recent evidence affirming the benefit of vaginal (micronized) progesterone to prevent PTB in women with a shortened cervix (<25mm). Given the low incidence of a short cervix at mid-gestation in high-risk populations further evidence is required. The objective of this review is to determine if vaginal progesterone reduces spontaneous preterm birth (sPTB) before 37 weeks in asymptomatic high-risk women with a singleton pregnancy with a normal mid-gestation cervical length. Methods: Studies will be sourced from MEDLINE and Embase databases with the search terms “progesterone” and “preterm birth”. Studies will be screened and included if they assess vaginal progesterone compared to placebo in women with a normal cervical length. The primary outcome will be sPTB <37 weeks, with secondary outcomes of sPTB <34 weeks. Two independent reviewers will conduct study screening at abstract and full text level, data extraction and risk of bias assessment with disagreements resolved by an experienced researcher. The Mantel-Haenszel statistical method and random effects analysis model will be used to produce treatment effect odds ratios and corresponding 95% confidence intervals.Discussion: This review will assess the current body of evidence and provide clarity regarding the potential benefits and best practice of use of vaginal progesterone in asymptomatic women with high risk singleton pregnancies and normal cervical length. Trial registration: This study has been registered on PROSPERO with the registration number CRD42020152051

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.