To determine the extent to which newborn's mid upper arm circumference (MUAC) could be used as a screening tool for low birth weight (LBW), we examined a total of 601 full-term, singleton babies delivered at Temeke District Hospital in Dar es Salaam, Tanzania, between January and April 1992. The mean birth weight and standard deviation (SD) was 2826 (+/-436) g and the MUAC (SD) 9.9 (+/-0.8) mt with a correlation coefficient of 0.88 between MUAC and birth weight (P=0.0001). The percentage of LBW (<2500 g) and an arm circumference below 9.5 cm were 18.8% and 11.8%, respectively. Use of 9.5 cm measurement as a cut-off point in MUAC was found to be a significant predictor of low birth weight. The sensitivity, specificity and positive predictive value were 57.5%, 98.8% and 91.6%, respectively. Newborns with a mid-upper-arm circumference <9.5 cm were 10 times more likely to have a LBW compared with an arm circumference greater than or equal to 9.5 cm (P=0.0001). In places where the conventional scales are not readily available MUAC of 9.5 cm could be used as a method to screen LBW babies in Tanzania. Significant maternal factors associated with LBW at the first antenatal clinic (ANC) booking included: weight <43.5 kg, height <150 cm, age of 14 to 19 years, positive malaria parasitemia and previous history of LBW. It is recommended that subjects with the above risk factors at ANC booking should be advised to deliver in hospital.
