Nutrition, sex, gestational age, and hair growth in babies.

Hair growth measurements are a sensitive indicator of nutrition and we have assessed their value in the perinatal period. The proportion of growing roots and their diameter were studied at birth in 114 babies and repeated 3 weeks later in 29 low birthweight babies. Intrauterine malnutrition resulted in thinner roots but the changes after birth were not related to nutrition and these measurements will not be useful in feeding studies in this period. At birth, gestational age and sex affected the hair root, and it may be important to recognise these differences if the hair root is used in biochemical screening tests. We have used a new simple technique for measuring the root diameter using an image-splitting eye-piece.