A random sample of 23 591 single livebirths was drawn from the Singapore Registry for 1967-1974, and information extracted from the birth certificates. The proportion of low birthweight infants (2500 g or less) fell markedly from 9.1% in 1967 to 5.7% in 1974, which has not been the finding in other studies. Variation in the proportions of low birthweight infants by sex, maternal age, parity, and social class, are broadly in agreement with other studies. Indians were found to have significantly smaller babies (mean weight of 3020 g) with a higher proportion of low birthweight ones (11.5%) than the Malays (3080 g and 8.1%) and the Chinese (3130 g and 6.1%). This is despite similar distributions of gestational age, and for term babies the differences in low birthweight proportions are highly significant with Chinese 5.0%, Malays 6.5%, and Indians 9.8%. The reasons for this are discussed with the implication that lower birthweights in Indians are to some extent of ethnic/genetic origin.
All singleton live births occurring in Singapore in the three years 1981-3 were computed, and birthweight was examined in the different ethnic groups (Chinese, Malay, and Indian). Overall the proportions of babies of very low birthweight (less than 1500 g) and low birthweight (less than 2500 g) were: Chinese 0.3% and 6.1%, Malays 0.4% and 8.5%, and Indians 0.5% and 10.0%. The important finding was that in all gestational periods and virtually all maternal age and live birth order groups Indians had the highest proportion of very low and low birthweight babies. However for prematurity Indians at 6.7% had a higher rate than Chinese (5.1%) but lower than Malays (9.9%). Likewise for neonatal mortality Indians at 8.7 per 1000 live births were between Chinese (7.1) and Malays (9.1). The evidence seems to indicate that the reason for Indians having a higher proportion of low birthweight babies is partly ethnic/genetic, and the cut-off point of 2500 g should perhaps be lowered for babies from the Indian subcontinent when international comparisons are being made.