Temporal trends and risk of small for gestational age (SGA) infants among Asian American mothers by ethnicity

To examine the temporal trends and risk of small for gestational age (SGA) phenotypes across Asian American ethnic groups. We conducted a population-based retrospective study using the 1992–2018 natality data files obtained from the National Vital Statistics System. Joinpoint regression modeling was employed to calculate the average annual percentage change in SGA birth rates among Asian American sub-groups and NH-White women. Logistic regression was utilized to compute the adjusted odds ratio and 95% confidence interval for the association between maternal race (Asian American sub-groups vs. NH-White) and SGA birth and its phenotypes. We analyzed data on 2,821,798 Asian Americans and 62,174,875 NH-White US live-born infants. Overall, NH-Whites had the lowest SGA rates, while all the Asian ethnic groups had almost consistently higher rates during the 27-year period. Disparity in SGA births in the Asian subgroups was observed. Compared to NH-Whites, stratified analyses showed varying and significantly higher odds of any SGA in all Asian ethnic groups. Asian Indians had the highest odds [adjusted odds ratio (AOR) = 2.23, 95% confidence interval (CI) = 2.22–2.23] of any SGA compared to NH-Whites. Our findings support the evidence that Asian Americans are not a homogenous group and highlight the need to disentangle these differences when conducting population health research and interventions among Asian Americans.