Asian/White Differences in the Relationship of Maternal Age to Low Birth Weight: Analysis of the PRAMS Survey, 2004–2011

This study aimed to examine (a) maternal age patterns of low birth weight (LBW; birth weight < 2,500 g) for non-Hispanic (N-H) Asian and N-H White women, and (b) Asian–White gaps in LBW risk by maternal age and their mechanisms. Logistic regression analyses were performed on the Pregnancy Risk Assessment Monitoring System data of N-H Asian and N-H White women who delivered their first singleton birth without birth defects in 13 states between 2004 and 2011. Ageand race/ethnicity-specific LBW risk was estimated, unadjusted and adjusted for maternal risk factors (e.g., marital status, maternal education, pregnancy intention, stress, maternal morbidities, smoking, and prenatal care) and their interactions with maternal age or race/ethnicity. The interaction between maternal age and race/ethnicity was statistically significant (p < .0001) with covariates and interactions held constant. N-H Asian women showed a reverse W-shaped maternal-age pattern of LBW with the highest risk in their late 30s (OR = 1.56, 95% CI [1.26, 1.94]) whereas N-H White women experienced a maternal age-related increase in LBW. N-H Asian women were more likely to deliver LBW infant than their N-H White counterparts between their late 20s and late 30s, with the greatest racial/ethnic gap in their late 20s (OR = 4.19, 95% CI [3.33, 5.29]). Preventive strategies should be developed targeting N-H Asian women aged 25 to 39 years to reduce the Asian–White disparities in LBW. Considering the known maternal risk factors failed to explain such disparities, future research is warranted to explore other risk factors unique to this at-risk population.