One size does not fit all: Examining ethnicity in gestational weight gain guidelines.

Pregnancy-related metrics vary by race/ethnicity, yet most gestational weight gain (GWG) guidelines are ethnicity-blind. We estimated small-for-gestational age (SGA) risk in a Japanese population, examining GWG adequacy categorized by Institute of Medicine (IOM) and Japanese guidelines in male (N  = 192) and female (N = 191) full-term singleton infants. For predicting SGA, IOM guidelines had high sensitivity ( ≥ 0.75), but low specificity ( ≤ 0.25); Japanese guidelines had high specificity ( ≥ 0.80) but low sensitivity ( ≤ 0.50). GWG guidelines' implicit notions of Caucasian-Americans as optimal may lead to 'One Size Fits All' recommendations that can obscure important biocultural factors contributing to maternal child health outcomes.