Exploring weathering: the relation of age to low birth weight among first generation and established United States-born Mexican-American women.

To determine the age-related patterns of low birth weight, preterm birth, and intrauterine growth retardation among first generation and established US-born Mexican-American mothers. We performed stratified analyses on an Illinois transgenerational dataset of Mexican-American infants (1989-1991) and their mothers (1956-1976) with appended U.S. census income information. In Cook County, Illinois established (second or higher generation) US-born Mexican-American women (N = 2,006) had a low birth weight (<2,500 g) rate of 6.2% compared to 4.8% for first generation US-born Mexican-American women (N = 1,450), RR = 1.3 (1.0-1.6). In both subgroups, low birth weight, preterm, and intrauterine growth retarded components rates did not increase with advancing maternal age. First generation 30-35 year old US-born Mexican-American women (N = 159) had a low birth weight rate of 3.1% compared to 4.2% for their teen counterparts (N = 386), RR = 0.8 (0.3-2.0). Established 30-35 year old US-born Mexican-American women (N = 330) had a low birth weight rate of 4.9% compared to 7.4% for their teen counterparts (N = 459), RR = 0.7 (0.4-1.2). There was no evidence of weathering among US-born Mexican-American mothers with a lifelong residence in lower income neighborhoods, with a general downward trend in low birth weight rates with increasing age until age 30-35. Rates of low birth weight, preterm birth, and intrauterine growth retardation do not increase with advancing age among first generation and established US-born 15-35 year old Mexican-American women. This trend persists among both generations of women with a lifelong residence in lower income neighborhoods.