Vásquez-Ruiz · Early human development 2014 · randomized controlled trial · n=38

A light/dark cycle in the NICU accelerates body weight gain and shortens time to discharge in preterm infants.

Cited 102 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 24831970 · doi:10.1016/j.earlhumdev.2014.04.015 · record verified 2026-08-31

What was done

Preterm infants born at 31.73 ± 0.31 weeks gestational age in the NICU of Hospital Juárez de México were randomized from birth to either an alternating light/dark cycle (LD, n=19) created using individual removable head helmets or traditional continuous light (LL, n=19). Investigators assessed body weight gain, hospital length of stay, oxygen saturation, and daily melatonin rhythms.

What was found

Infants in the light/dark group experienced faster weight gain and had a significantly shorter hospital stay than those under continuous light (34.37 ± 3.12 vs 51.11 ± 5.29 days; reported in abstract as P>0.01). Infants in the LD group also demonstrated improved oxygen saturation and developed a daily melatonin rhythm. Exact numeric values for weight gain velocity, oxygen saturation, and melatonin levels were not provided in the abstract.

Why it matters

Using individual head-covering helmets offers a simple, low-cost method to establish circadian light/dark cycles in open NICU environments, potentially reducing hospitalization time and supporting physiological stability.

Limits

The sample size was very small (n=19 per arm) and recruited from a single center. The study evaluated moderately preterm infants (~31.7 weeks), limiting generalizability to extremely preterm infants. The abstract omits numerical data for weight gain, oxygenation, and melatonin parameters, and contains a likely typographical error reporting significance as P>0.01.

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