Weight gain and movement patterns of very low birthweight babies nursed on lambswool

34 very low birthweight babies (mean 1143 g) in incubators were randomly assigned to be continuously nursed on lambswool (n = 17) or ordinary cotton sheets (n = 17). The weight gain for the periods when babies were well was significantly larger for the wool group, 22.7 g/day vs 18.6 g/day for cotton control (p less than 0.02). The overall weight gain (which included weight change during periods of illness) revealed a similar picture in favour of the wool group, 21.5 g/day vs 18.2 g/day (p less than 0.05). Movement patterns for the two groups showed no differences, but for all babies a strong correlation was noted between moving and lying suspine (p less than 0.001), having eyes open (p less than 0.001), a cooler incubator (p less than 0.01), and faster weight gain (p less than 0.01). Lambswool seems to have advantages over cotton sheets as a bedding material for very low birth weight babies.