[Perimeters of the arm and the thorax as indicators of low birth weight].

In a group of 317 newborns, measurements of the perimeter of the arm and the thorax were taken as an indicator of low birth weight. The perimeters of both the arm and the thorax had a high correlation with low birth weight (LBW) (0.88-0.80 respectively). In the sample group, the cut-off point to define low birth weight in the case of perimeter of the arm was 9 cm and was 29-30 cm for perimeter of the thorax. Applying these measurements facilitates early detection and treatment of low birth weight babies who are at risk for infant mortality in situations where it is not possible to weigh the baby at birth.