Effect of timing of umbilical cord clamping and other strategies to influence placental transfusion at preterm birth on maternal and infant outcomes

BACKGROUND

Infants born preterm (before 37 weeks' gestation) have poorer outcomes than infants at term, particularly if born before 32 weeks. Early cord clamping has been standard practice over many years, and enables quick transfer of the infant to neonatal care. Delayed clamping allows blood flow between the placenta, umbilical cord and baby to continue, and may aid transition. Keeping baby at the mother's side enables neonatal care with the cord intact and this, along with delayed clamping, may improve outcomes. Umbilical cord milking (UCM) is proposed for increasing placental transfusion when immediate care for the preterm baby is needed. This Cochrane Review is a further update of a review first published in 2004 and updated in 2012.

OBJECTIVES

To assess the effects on infants born at less than 37 weeks' gestation, and their mothers of: 1) delayed cord clamping (DCC) compared with early cord clamping (ECC) both with immediate neonatal care after cord clamping; 2) DCC with immediate neonatal care with cord intact compared with ECC with immediate neonatal care after cord clamping; 3) DCC with immediate neonatal care after cord clamping compared with UCM; 4) UCM compared with ECC with immediate neonatal care after cord clamping.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (10 November 2017), and reference lists of retrieved studies. We updated the search in November 2018 and added nine new trial reports to the awaiting classification section to be assessed at the next update.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing delayed with early clamping of the umbilical cord (with immediate neonatal care after cord clamping or with cord intact) and UCM for births before 37 weeks' gestation. Quasi-RCTs were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Random-effects are used in all meta-analyses. Review authors assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

This update includes forty-eight studies, involving 5721 babies and their mothers, with data available from 40 studies involving 4884 babies and their mothers. Babies were between 24 and 36+6 weeks' gestation at birth and multiple births were included. The data are mostly from high-income countries. Delayed clamping ranged between 30 to 180 seconds, with most studies delaying for 30 to 60 seconds. Early clamping was less than 30 seconds and often immediate. UCM was mostly before cord clamping but some were milked after cord clamping. We undertook subgroup analysis by gestation and type of intervention, and sensitivity analyses by low risk of selection and attrition bias.All studies were high risk for performance bias and many were unclear for other aspects of risk of bias. Certainty of the evidence using GRADE was mostly low, mainly due to imprecision and unclear risk of bias.Delayed cord clamping (DCC) versus early cord clamping (ECC) both with immediate neonatal care after cord clamping (25 studies, 3100 babies and their mothers)DCC probably reduces the number of babies who die before discharge compared with ECC (average risk ratio (aRR) 0.73, 95% confidence interval (CI) 0.54 to 0.98, 20 studies, 2680 babies (moderate certainty)).No studies reported on 'Death or neurodevelopmental impairment' in the early years'.DCC may make little or no difference to the number of babies with severe intraventricular haemorrhage (IVH grades 3 and 4) (aRR 0.94, 95% CI 0.63 to 1.39, 10 studies, 2058 babies, low certainty) but slightly reduces the number of babies with any grade IVH (aRR 0.83, 95% CI 0.70 to 0.99, 15 studies, 2333 babies, high certainty).DCC has little or no effect on chronic lung disease (CLD) (aRR 1.04, 95% CI 0.94 to 1.14, 6 studies, 1644 babies, high certainty).Due to insufficient data, we were unable to form conclusions regarding periventricular leukomalacia (PVL) (aRR 0.58, 95% CI 0.26 to 1.30, 4 studies, 1544 babies, low certainty) or maternal blood loss of 500 mL or greater (aRR 1.14, 95% CI 0.07 to 17.63, 2 studies, 180 women, very low certainty).We identified no important heterogeneity in subgroup or sensitivity analyses.Delayed cord clamping (DCC) with immediate neonatal care with cord intact versus early cord clamping (ECC) (one study, 276 babies and their mothers)There are insufficient data to be confident in our findings, but DCC with immediate neonatal care with cord intact may reduce the number of babies who die before discharge, although the data are also compatible with a slight increase in mortality, compared with ECC (aRR 0.47, 95% CI 0.20 to 1.11, 1 study, 270 babies, low certainty). DCC may also reduce the number of babies who die or have neurodevelopmental impairment in early years (aRR 0.61, 95% CI 0.39 to 0.96, 1 study, 218 babies, low certainty). There may be little or no difference in: severe IVH; all grades IVH; PVL; CLD; maternal blood loss ≥ 500 mL, assessed as low certainty mainly due to serious imprecision.Delayed cord clamping (DCC) with immediate neonatal care after cord clamping versus umbilical cord milking (UCM) (three studies, 322 babies and their mothers) and UCM versus early cord clamping (ECC) (11 studies, 1183 babies and their mothers)There are insufficient data for reliable conclusions about the comparative effects of UCM compared with delayed or early clamping (mostly low or very low certainty).

AUTHORS' CONCLUSIONS

Delayed, rather than early, cord clamping may reduce the risk of death before discharge for babies born preterm. There is insufficient evidence to show what duration of delay is best, one or several minutes, and therefore the optimum time to clamp the umbilical cord remains unclear. Whilst the current evidence supports not clamping the cord before 30 seconds at preterm births, future trials could compare different lengths of delay. Immediate neonatal care with the cord intact requires further study, and there are insufficient data on UCM.The nine new reports awaiting further classification may alter the conclusions of the review once assessed.

Kangaroo mother care to reduce morbidity and mortality in low birthweight infants

BACKGROUND

Kangaroo mother care (KMC), originally defined as skin-to-skin contact between a mother and her newborn, frequent and exclusive or nearly exclusive breastfeeding, and early discharge from hospital, has been proposed as an alternative to conventional neonatal care for low birthweight (LBW) infants.

OBJECTIVES

To determine whether evidence is available to support the use of KMC in LBW infants as an alternative to conventional neonatal care before or after the initial period of stabilization with conventional care, and to assess beneficial and adverse effects.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches in CENTRAL (Cochrane Central Register of Controlled Trials; 2016, Issue 6), MEDLINE, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), LILACS (Latin American and Caribbean Health Science Information database), and POPLINE (Population Information Online) databases (all from inception to June 30, 2016), as well as the WHO (World Health Organization) Trial Registration Data Set (up to June 30, 2016). In addition, we searched the web page of the Kangaroo Foundation, conference and symposia proceedings on KMC, and Google Scholar.

SELECTION CRITERIA

Randomized controlled trials comparing KMC versus conventional neonatal care, or early-onset KMC versus late-onset KMC, in LBW infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed according to the methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

Twenty-one studies, including 3042 infants, fulfilled inclusion criteria. Nineteen studies evaluated KMC in LBW infants after stabilization, one evaluated KMC in LBW infants before stabilization, and one compared early-onset KMC with late-onset KMC in relatively stable LBW infants. Sixteen studies evaluated intermittent KMC, and five evaluated continuous KMC. KMC versus conventional neonatal care: At discharge or 40 to 41 weeks' postmenstrual age, KMC was associated with a statistically significant reduction in the risk of mortality (risk ratio [RR] 0.60, 95% confidence interval [CI] 0.39 to 0.92; eight trials, 1736 infants), nosocomial infection/sepsis (RR 0.35, 95% CI 0.22 to 0.54; five trials, 1239 infants), and hypothermia (RR 0.28, 95% CI 0.16 to 0.49; nine trials, 989 infants; moderate-quality evidence). At latest follow-up, KMC was associated with a significantly decreased risk of mortality (RR 0.67, 95% CI 0.48 to 0.95; 12 trials, 2293 infants; moderate-quality evidence) and severe infection/sepsis (RR 0.50, 95% CI 0.36 to 0.69; eight trials, 1463 infants; moderate-quality evidence). Moreover, KMC was found to increase weight gain (mean difference [MD] 4.1 g/d, 95% CI 2.3 to 5.9; 11 trials, 1198 infants; moderate-quality evidence), length gain (MD 0.21 cm/week, 95% CI 0.03 to 0.38; three trials, 377 infants) and head circumference gain (MD 0.14 cm/week, 95% CI 0.06 to 0.22; four trials, 495 infants) at latest follow-up, exclusive breastfeeding at discharge or 40 to 41 weeks' postmenstrual age (RR 1.16, 95% CI 1.07 to 1.25; six studies, 1453 mothers) and at one to three months' follow-up (RR 1.20, 95% CI 1.01 to 1.43; five studies, 600 mothers), any (exclusive or partial) breastfeeding at discharge or at 40 to 41 weeks' postmenstrual age (RR 1.20, 95% CI 1.07 to 1.34; 10 studies, 1696 mothers; moderate-quality evidence) and at one to three months' follow-up (RR 1.17, 95% CI 1.05 to 1.31; nine studies, 1394 mothers; low-quality evidence), and some measures of mother-infant attachment and home environment. No statistically significant differences were found between KMC infants and controls in Griffith quotients for psychomotor development at 12 months' corrected age (low-quality evidence). Sensitivity analysis suggested that inclusion of studies with high risk of bias did not affect the general direction of findings nor the size of the treatment effect for main outcomes. Early-onset KMC versus late-onset KMC in relatively stable infants: One trial compared early-onset continuous KMC (within 24 hours post birth) versus late-onset continuous KMC (after 24 hours post birth) in 73 relatively stable LBW infants. Investigators reported no significant differences between the two study groups in mortality, morbidity, severe infection, hypothermia, breastfeeding, and nutritional indicators. Early-onset KMC was associated with a statistically significant reduction in length of hospital stay (MD 0.9 days, 95% CI 0.6 to 1.2).

AUTHORS' CONCLUSIONS

Evidence from this updated review supports the use of KMC in LBW infants as an alternative to conventional neonatal care, mainly in resource-limited settings. Further information is required concerning the effectiveness and safety of early-onset continuous KMC in unstabilized or relatively stabilized LBW infants, as well as long-term neurodevelopmental outcomes and costs of care.