Deferred cord clamping, cord milking, and immediate cord clamping at preterm birth: a systematic review and individual participant data meta-analysis

BACKGROUND

Umbilical cord clamping strategies at preterm birth have the potential to affect important health outcomes. The aim of this study was to compare the effectiveness of deferred cord clamping, umbilical cord milking, and immediate cord clamping in reducing neonatal mortality and morbidity at preterm birth.

METHODS

We conducted a systematic review and individual participant data meta-analysis. We searched medical databases and trial registries (from database inception until Feb 24, 2022; updated June 6, 2023) for randomised controlled trials comparing deferred (also known as delayed) cord clamping, cord milking, and immediate cord clamping for preterm births (<37 weeks' gestation). Quasi-randomised or cluster-randomised trials were excluded. Authors of eligible studies were invited to join the iCOMP collaboration and share individual participant data. All data were checked, harmonised, re-coded, and assessed for risk of bias following prespecified criteria. The primary outcome was death before hospital discharge. We performed intention-to-treat one-stage individual participant data meta-analyses accounting for heterogeneity to examine treatment effects overall and in prespecified subgroup analyses. Certainty of evidence was assessed with Grading of Recommendations Assessment, Development, and Evaluation. This study is registered with PROSPERO, CRD42019136640.

FINDINGS

We identified 2369 records, of which 48 randomised trials provided individual participant data and were eligible for our primary analysis. We included individual participant data on 6367 infants (3303 [55%] male, 2667 [45%] female, two intersex, and 395 missing data). Deferred cord clamping, compared with immediate cord clamping, reduced death before discharge (odds ratio [OR] 0·68 [95% CI 0·51-0·91], high-certainty evidence, 20 studies, n=3260, 232 deaths). For umbilical cord milking compared with immediate cord clamping, no clear evidence was found of a difference in death before discharge (OR 0·73 [0·44-1·20], low certainty, 18 studies, n=1561, 74 deaths). Similarly, for umbilical cord milking compared with deferred cord clamping, no clear evidence was found of a difference in death before discharge (0·95 [0·59-1·53], low certainty, 12 studies, n=1303, 93 deaths). We found no evidence of subgroup differences for the primary outcome, including by gestational age, type of delivery, multiple birth, study year, and perinatal mortality.

INTERPRETATION

This study provides high-certainty evidence that deferred cord clamping, compared with immediate cord clamping, reduces death before discharge in preterm infants. This effect appears to be consistent across several participant-level and trial-level subgroups. These results will inform international treatment recommendations.

FUNDING

Australian National Health and Medical Research Council.

Short, medium, and long deferral of umbilical cord clamping compared with umbilical cord milking and immediate clamping at preterm birth: a systematic review and network meta-analysis with individual participant data

BACKGROUND

Deferred (also known as delayed) cord clamping can improve survival of infants born preterm (before 37 weeks of gestation), but the optimal duration of deferral remains unclear. We conducted a systematic review and individual participant data network meta-analysis with the aim of comparing the effectiveness of umbilical cord clamping strategies with different timings of clamping or with cord milking for preterm infants.

METHODS

We searched medical databases and trial registries from inception until Feb 24, 2022 (updated June 6, 2023) for randomised controlled trials comparing cord clamping strategies for preterm infants. Individual participant data were harmonised and assessed for risk of bias and quality. Interventions were grouped into immediate clamping, short deferral (≥15 s to <45 s), medium deferral (≥45 s to <120 s), long deferral (≥120 s), and intact cord milking. The primary outcome was death before hospital discharge. We calculated one-stage, intention-to-treat Bayesian random-effects individual participant data network meta-analysis. This study was registered with PROSPERO, CRD42019136640.

FINDINGS

We included individual participant data from 47 trials with 6094 participants. Of all interventions, long deferral reduced death before discharge the most (compared with immediate clamping; odds ratio 0·31 [95% credibility interval] 0·11-0·80; moderate certainty). The risk of bias was low for 10 (33%) of 30 trials, 14 (47%) had some concerns, and 6 (20%) were rated as having a high risk of bias. Heterogeneity was low, with no indication of inconsistency.

INTERPRETATION

This study found that long deferral of clamping leads to reduced odds of death before discharge in preterm infants. In infants assessed as requiring immediate resuscitation, this finding might only be generalisable if there are provisions for such care with the cord intact. These results are based on thoroughly cleaned and checked individual participant data and can inform future guidelines and practice.

FUNDING

Australian National Health and Medical Research Council.

Optimizing cord management for each preterm baby - Challenges of collating individual participant data and recommendations for future collaborative research

The optimal cord management strategy at birth for each preterm baby is still unknown, despite more than 100 randomized controlled trials (RCTs) undertaken on this question. To address this, we brought together all RCTs examining cord management strategies at preterm birth in the iCOMP (individual participant data on COrd Management at Preterm birth) Collaboration, to perform an individual participant data network meta-analysis. In this paper, we describe the trials and tribulations around obtaining individual participant data to resolve controversies around cord clamping, and we derive key recommendations for future collaborative research in perinatology. To reliably answer outstanding questions, future cord management research needs to be collaborative and coordinated, by aligning core protocol elements, ensuring quality and reporting standards are met, and carefully considering and reporting on vulnerable sub-populations. The iCOMP Collaboration is an example of the power of collaboration to address priority research questions, and ultimately improve neonatal outcomes worldwide.

Development of a checklist of standard items for processing individual participant data from randomised trials for meta-analyses: Protocol for a modified e-Delphi study

Individual participant data meta-analyses enable detailed checking of data quality and more complex analyses than standard study-level synthesis of summary data based on publications. However, there is limited existing guidance on the specific systematic checks that should be undertaken to confirm and enhance data quality for individual participant data meta-analyses and how to conduct these checks. We aim to address this gap by developing a checklist of items for data quality checking and cleaning to be applied to individual participant data meta-analyses of randomised trials. This study will comprise three phases: 1) a scoping review to identify potential checklist items; 2) two e-Delphi survey rounds among an invited panel of experts followed by a consensus meeting; and 3) pilot testing and refinement of the checklist, including development of an accompanying R-markdown program to facilitate its uptake.

Transforming Obesity Prevention for CHILDren (TOPCHILD) Collaboration: protocol for a systematic review with individual participant data meta-analysis of behavioural interventions for the prevention of early childhood obesity

INTRODUCTION

Behavioural interventions in early life appear to show some effect in reducing childhood overweight and obesity. However, uncertainty remains regarding their overall effectiveness, and whether effectiveness differs among key subgroups. These evidence gaps have prompted an increase in very early childhood obesity prevention trials worldwide. Combining the individual participant data (IPD) from these trials will enhance statistical power to determine overall effectiveness and enable examination of individual and trial-level subgroups. We present a protocol for a systematic review with IPD meta-analysis to evaluate the effectiveness of obesity prevention interventions commencing antenatally or in the first year after birth, and to explore whether there are differential effects among key subgroups.

METHODS AND ANALYSIS

Systematic searches of Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycInfo and trial registries for all ongoing and completed randomised controlled trials evaluating behavioural interventions for the prevention of early childhood obesity have been completed up to March 2021 and will be updated annually to include additional trials. Eligible trialists will be asked to share their IPD; if unavailable, aggregate data will be used where possible. An IPD meta-analysis and a nested prospective meta-analysis will be performed using methodologies recommended by the Cochrane Collaboration. The primary outcome will be body mass index z-score at age 24±6 months using WHO Growth Standards, and effect differences will be explored among prespecified individual and trial-level subgroups. Secondary outcomes include other child weight-related measures, infant feeding, dietary intake, physical activity, sedentary behaviours, sleep, parenting measures and adverse events.

ETHICS AND DISSEMINATION

Approved by The University of Sydney Human Research Ethics Committee (2020/273) and Flinders University Social and Behavioural Research Ethics Committee (HREC CIA2133-1). Results will be relevant to clinicians, child health services, researchers, policy-makers and families, and will be disseminated via publications, presentations and media releases.

PROSPERO REGISTRATION NUMBER

CRD42020177408.

Unpacking the behavioural components and delivery features of early childhood obesity prevention interventions in the TOPCHILD Collaboration: a systematic review and intervention coding protocol

INTRODUCTION

Little is known about how early (eg, commencing antenatally or in the first 12 months after birth) obesity prevention interventions seek to change behaviour and which components are or are not effective. This study aims to (1) characterise early obesity prevention interventions in terms of target behaviours, delivery features and behaviour change techniques (BCTs), (2) explore similarities and differences in BCTs used to target behaviours and (3) explore effectiveness of intervention components in preventing childhood obesity.

METHODS AND ANALYSIS

Annual comprehensive systematic searches will be performed in Epub Ahead of Print/MEDLINE, Embase, Cochrane (CENTRAL), CINAHL, PsycINFO, as well as clinical trial registries. Eligible randomised controlled trials of behavioural interventions to prevent childhood obesity commencing antenatally or in the first year after birth will be invited to join the Transforming Obesity in CHILDren Collaboration. Standard ontologies will be used to code target behaviours, delivery features and BCTs in both published and unpublished intervention materials provided by trialists. Narrative syntheses will be performed to summarise intervention components and compare applied BCTs by types of target behaviours. Exploratory analyses will be undertaken to assess effectiveness of intervention components.

ETHICS AND DISSEMINATION

The study has been approved by The University of Sydney Human Research Ethics Committee (project no. 2020/273) and Flinders University Social and Behavioural Research Ethics Committee (project no. HREC CIA2133-1). The study's findings will be disseminated through peer-reviewed publications, conference presentations and targeted communication with key stakeholders.

PROSPERO REGISTRATION NUMBER

CRD42020177408.

1477The landscape of COVID-19 trials in Australia

Background

The coronavirus disease 2019 (COVID-19) pandemic has seen a large number of clinical trials launched at unprecedented speed. We aimed to explore the landscape of COVID-19 trials in Australia, and to what extent Australian researchers have responded to global need for coordination and collaboration.

Methods

We systematically searched the Australian New Zealand Clinical Trials Registry (ANZCTR) and ClinicalTrials.gov from 1st January to 16th November 2020. We included all interventional studies addressing prevention, diagnosis or treatment of COVID-19, recruiting in Australia. We analysed the number and size of trials, additional recruitment countries, funding, trial purpose, study design, data sharing plans, and collection of COVID-19 core outcomes.

Results

We identified 56 COVID-19 trials, targeting 33,757 participants. They evaluated drugs (n = 34, 61%), vaccines (n = 10, 18%) or other interventions (n = 12, 21%), e.g. ventilators, digital health. Median target sample size was 150 (Q1-Q3=33-395). Only two trials utilised adaptive methods (Bayesian designs), and of the 34 COVID-19 treatment trials, only one included all core outcomes. Most (80%) indicated they were not planning to share data.

Conclusions

There has been impressive research scale-up and innovation in drug development and digital health, but fast-track procedures may have impacted scientific rigor and research prioritisation. Trials often lacked innovative study designs, were underpowered for clinical outcomes, collected limited core outcomes and did not intend to share data, precluding future evidence synthesis.

Key messages

The research response in Australia has been rapid, but better coordination is required. Infrastructure for innovation would support coordination of research efforts, and reduce research waste.