The aetiology of low birthweight in a rural area of Tanzania.

In a hospital-based study, birthweights of 3162 consecutive births were related to perinatal mortality, multiple birth, and gestational age. Independent associations between 15 potential determinants and low birthweight, prematurity and small-at-term factors were also assessed. A newly constructed local curve of birthweight-for-gestational age is compared with the existing curves. The variables positively associated with low birthweight (< 2500 g) were nulliparity, vomiting as a self-reported complaint, spleen enlargement, sex of the infant and previous perinatal mortality. Nulliparity and spleen enlargement were positively associated with preterm birth, while small-at-birth was mostly associated with nulliparity and sex of the infant. Further study on spleen enlargement, the only modifiable factor in this study of possible public health importance, is warranted. Other factors of potential importance which deserve further investigations are hard physical work, maternal morbidity and antenatal care.