Enigma of maternal race and infant birth weight: a population-based study of US-born Black and Caribbean-born Black women.

The authors used 1985-1990 Illinois' vital records to determine the low birth weight components of infants delivered to US-born Black women, Caribbean-born Black women, and US-born White women. The moderately low birth weight rate (1,500-2,499 g) was 10% for infants with US-born Black mothers (n = 67,357) and 6% for infants with Caribbean-born mothers (n = 2,265) compared with 4% for infants with US-born White mothers (n = 34,124); the relative risk equaled 2.7 (95% confidence interval (CI): 2.5, 2.8) and 1.7 (95% CI: 1.4, 2.0), respectively. The very low birth weight rate (<1,500 g) was 2.6% for infants delivered to US-born Black women and 2.4% for infants to Caribbean-born women compared with 0.7% for infants to US-born White women; the relative risk equaled 3.6 (95% CI: 3.1, 4.1) and 3.3 (95% CI: 2.5, 4.4), respectively. Among the lowest risk mothers, the relative risk of moderately low birth weight for infants with US-born Black mothers and Caribbean-born mothers (compared with US-born White mothers) was 2.7 (95% CI: 2.1, 3.4) and 1.2 (95% CI: 0.4, 3.1), respectively; the relative risk of very low birth weight for infants with US-born Black mothers and Caribbean-born mothers was 6.7 (95% CI: 3.8, 12) and 4.2 (95% CI: 1.0, 18), respectively. The authors conclude that Caribbean-born women and US-born Black women have disparate moderate rates but equivalent very low birth weight rates.