Third Generation Consequences of Small for Gestational Age Births

To ascertain whether former small for gestational age (weight-for-gestational age < 10th percentile, SGA), compared to non-SGA, US-born women have greater SGA rates in their grandchildren.

A multi-step strategy utilizing mother's date of birth and full name was used to link the vital records of Chicago-born infants (born 2005-2017) to the Illinois transgenerational birth-file of their mothers (born 1989-1991) and maternal grandmothers (born 1956-1976). These matches accounted for differing naming practices, misspellings, and typographical errors. Our population was used to define generation-one women's SGA based on sex. A population-based reference was used to define generation-three infant's SGA based on sex average birthweight. Stratified and multivariable log binomial regression analyses were performed on singleton births. The Population Attributable Risk (PAR) percentages were calculated: P_E|D * [(adjRR-1)/adjRR] were calculated.

Former SGA women (n = 1510) had a greater percentage of SGA births in their grandchildren than former non-SGA women (n = 9466): 23.3% versus 17.6%; RR = 1.30 (1.14, 1.52). The adjusted (controlling for daughters' selected covariates including race, education, prenatal care usage, and cigarette smoking) RR of grandchildren SGA among former SGA (compared to non-SGA) women equaled 1.22 (1.09, 1.36). The PAR of maternal grandmother's SGA status equaled 4.3% percent among African-Americans. There were too few non-Latina White women to calculate a meaningful PAR%.

In the US, urban women who were themselves born SGA (compared to non-SGA) have a modest increased SGA frequency in their grandchildren. A small percentage of SGA African-American births is attributable to their maternal grandmother's SGA status.