Intergenerational Change in Birthweight: Effects of Foreign-born Status and Race/Ethnicity

Abstract

Background: Foreign-born women have heavier infants than US-born women, but it is unclear whether this advantage persists across generations for all races and ethnicities.

Methods: Using 1971-2015 Florida birth records, we linked records of female infants within families to assess intergenerational changes in birthweight and prevalence of low birthweight by grandmother's race/ethnicity and foreign-born status. We also assessed educational gradients in low birthweight in two generations.

Results: Compared with daughters of US-born black women, daughters of foreign-born black women had substantially higher birthweights (3,199 vs. 3,083 g) and lower prevalence of low birthweight (7.8% vs. 11.8%). Daughters of foreign-born Hispanic women had moderately higher birthweights (3,322 vs. 3,268 grams) and lower prevalence of low birthweight (4.5% vs. 6.2%) than daughters of US-born Hispanic women. In the next generation, a Hispanic foreign-origin advantage persisted in low birthweight prevalence (6.1% vs. 7.2%), but the corresponding black foreign-origin advantage was almost eliminated (12.2% vs. 13.1%). Findings were robust to adjustment for sociodemographic and medical risk factors. In contrast to patterns for other women, the prevalence of low birthweight varied little by maternal education for foreign-born black women. However, a gradient emerged among their US-born daughters.

Conclusions: The convergence of birthweight between descendants of foreign-born and US-born black women is consistent with theories positing that lifetime exposure to discrimination and socioeconomic inequality is associated with adverse health outcomes for black women. The emergence of a distinct educational gradient in low birthweight prevalence between generations underscores hypothesized adverse effects of multiple dimensions of disadvantage.

FIGURE 1.

Educational gradients in the prevalence of low birthweight by G1 race/ethnicity and foreign-born status in both generations. Observed prevalence of low birthweight by mother’s education in (A) G2 births and (B) G3 births.

FIGURE 2.

G1 Race/Ethnicity and Foreign-Born Status. Predicted birthweight in G3 by G1 race/ethnicity and foreign-born status. Predictions were generated by assigning G2 birthweight values to their group-specific means and holding all other covariates in the models except for G1 race/ethnicity and foreign-born status at their mean values for the entire sample. Coefficients from these models are displayed in eTable 2; http://links.lww.com/EDE/B687. Error bars indicate the 95% confidence interval for the prediction.

FIGURE 3.

G1 Race/Ethnicity and Foreign-Born Status. Predicted probability of low birthweight in G3 by G1 race/ethnicity and foreign-born status. Predictions were generated by assigning G2 birthweight values to their group-specific means and holding all other covariates in the models except for G1 race/ethnicity and foreign-born status at their mean values for the entire sample. Coefficients from these models are displayed in eTable 2; http://links.lww.com/EDE/B687. Error bars indicate the 95% confidence interval for the prediction.