Selected preconception health indicators and birth weight disparities in a national study

This analysis explored the effect of timing, sequencing, and change in preconception health across adolescence and young adulthood on racial/ethnic disparities in birth weight in a diverse national cohort of young adult women.

Data came from Waves I (1994-1995), III (2001-2002), and IV (2007-2008) of the National Longitudinal Study of Adolescent Health. Eligibility was restricted to all singleton live births to female non-Hispanic White, non-Hispanic Black, Mexican-origin Latina, or Asian/Pacific Islander participants (n = 3,014) occurring between the Wave III (ages 18-26 years) and IV (ages 24-32 years) interviews. Birth weight was categorized into low (<2,500 g), normal (2,500-4,000 g), and macrosomic (>4,000 g). Preconception health indicators were cigarette smoking, heavy alcohol consumption, overweight or obesity, and inadequate physical activity, measured in adolescence (Wave I, ages 11-19 years) and early adulthood (Wave III) and combined into four-category variables to capture the timing and sequencing of exposure.

Measures of preconception health did not explain the Black-White disparity in low birth weight, which increased after adjustment for confounders (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.33-3.53) and effect modification by overweight/obesity (OR, 3.58; 95% CI, 1.65-7.78). A positive association between adult-onset overweight/obesity and macrosomia was modified by race (OR, 3.83; 95% CI, 1.02-14.36 for Black women).

This longitudinal analysis provides new evidence on preconception health and racial/ethnic disparities in birth weight. Specifically, it indicates that interventions focused on prevention of overweight/obesity and maintenance of healthy weight during the transition to adulthood, especially among Black females, may be warranted.