Birth Anthropometry Predicts Neonatal and Infant Mortality in Rural Bangladesh: A Focus on Circumferential Measurements

Abstract

Background: Risk of infant death is increased in small newborns. Weight and length are typically measured at birth while circumferences are less often assessed. We investigated abilities of birth length, weight, and mid-upper arm (MUAC), head (HC) and chest (CC) circumferences to predict infant mortality in rural northwest Bangladesh. Methods: Singletons born during an antenatal micronutrient supplementation trial (n=21 174) were measured < 72 hours of birth. Vital status was prospectively recorded throughout infancy, identifying 583 deaths. Optimal cut-offs for predicting neonatal (NMR ≤28 days) and infant (IMR ≤365 days) mortality for each measurement were informed by the Youden Index (sensivity+specificity-1). Relative Risk Ratios (RRRs) and positive predictive values (PPVs) were calculated at cut-offs throughout the range of each measurement, and for indices combining any two. Results: Predictive cutoffs, harmonized to 100 g or 0·5 cm readings, for both NMR and IMR were 44.5 cm for length, 2200 g for weight, 9·0 cm for MUAC, 31·0 cm for HC, and for 28·5 cm CC. A CC <28·5 cm, alone and combined with HC <31·0 cm, versus higher values, yielded highest RRRs [9·68 (95% CI:7·84-11·94) and 15.74 (95% CI:12·54-19·75)] and PPVs (11·3% and 16·3%) for neonatal and infant [RRRs=6.02 (95% CI:5·15-7·02) and 9.19 (95% CI:7·72-10·95) and PPVs (10·7% and 14·6%)] mortality. At harmonized cut-offs, all indices revealed higher RRRs (range:5·34-9·19) and PPVs (range:8·5%-14·5%) than individual measurements (ranges:3·40-6·02 and 6·4%-16·3%, respectively). Conclusions: In rural Bangladesh, chest circumference alone or combined with head circumference was more predictive of neonatal and infant mortality than other measurements. Trial Registration: ClinicalTrials.gov INCT00860470 Funding Statement: Bill & Melinda Gates Foundation (Grants GH614 and OPP1441435, Senior Program Officer: Ellen Piwoz), Seattle, WA, USA and the Sight and Life Global Nutrition Research Institute (Klaus Kraemer), Baltimore MD. Declaration of Interests: None. Ethics Approval Statement: Verbal informed consent was obtained from mothers prior to enrollment in the trial. The study protocol was approved by the Johns Hopkins Bloomberg School of Public Health Institutional Review Board, Baltimore, Maryland, and the Bangladesh Medical Research Council, Dhaka, Bangladesh.