Early postnatal weight loss and its association with outcomes in very preterm neonates: a systematic review and meta-analysis.

Ideal early postnatal weight loss (PWL) and its association with mortality and morbidity in preterm infants is not well known. This review explored the association between early PWL and outcomes in very premature infants (<32 weeks). This is a systematic review and meta-analyses of the observational studies. PubMed, Medline, EMBASE, Cochrane Library, EMCARE and MedNar databases were searched in April 2024. Outcomes of interest were mortality and morbidities such as intraventricular-haemorrhage (IVH), chronic lung disease (CLD), patent ductus arteriosus (PDA), necrotising enterocolitis (NEC), retinopathy of prematurity (ROP) and long-term neurodevelopmental outcomes. Data were pooled separately for adjusted and unadjusted odds ratios (ORs) using random-effects model. Separate analyses were conducted for case-control and cohort studies. Data were pooled separately for the excess weight loss (EWL) group (>15% from birth weight) and inadequate weight loss (IWL) group (<5% from birth weight). Eighteen studies (25158 infants) were included. Pooling of adjusted ORs in EWL group from cohort studies found significant association with mortality (OR 1.39 CI (1.10 to1.75)), severe IVH (OR 1.37 CI (1.18 to1.59)), NEC (OR 2.05 CI (1.05 to4.03)) and "Mortality or IVH" (OR 1.40 CI (1.10 to1.78)). Pooling adjusted ORs from case-control studies showed a significant association between EWL and CLD, and between IWL and mortality or CLD. Certainty of evidence was 'Low' or 'Very-low'. EWL or IWL in very-preterm infants may be associated with higher odds of mortality and morbidity. However, cofactors of severity of associated disease, insufficient nutrition, and treatments could not be assessed.