Maternal fat intake at pregnancy tied to higher offspring weight

Pregnant women with increased fat intake, particularly trans fat, are more likely to deliver offspring with a higher body weight, suggests a study. Consumption of other macronutrients from various food sources, however, does not appear to affect offspring weight.

A total of 5,715 children (mean age 11.8 years at baseline in 2004) from the Growing Up Today Study 2 born to 4,731 mothers who participated in the Nurses’ Health Study II during 1989–1995 were included in this prospective analysis.

A validated food frequency questionnaire (FFQ) in 1991 and 1995 was used to assess diet during or before pregnancy. Overweight and obesity in childhood and adolescence were defined using age- and sex-specific BMI. Finally, the investigators explored the associations of interest using multivariable linear and log-binomial regression models with generalized estimating equations.

During pregnancy, the mean maternal macronutrient percent energy intake was 19.3 percent for protein, 51.2 percent for carbohydrates, and 30.8 percent for total fat.

After multivariate adjustment for maternal and offspring risk factors, the highest quartile of trans fatty acid intake during pregnancy correlated with a 0.20-unit (95 percent confidence interval [CI], 0.00–0.40) increase in BMI z-score without a significant linear trend (p=0.06) compared with the lowest quartile.

Total fat intake also correlated with BMI z-score (β, 0.21, 95 percent CI, 0.05–0.36; p=0.02) when replacing total carbohydrate and vice versa (β, –0.24, 95 percent CI, –0.40 to –0.08; p=0.02 for total carbohydrate intake).

In addition, none of the other macronutrients consumed before pregnancy showed an association with offspring BMI z-score or the risk of overweight or obesity.

“Overall, these data suggest that, apart from trans fatty acids, other macronutrient composition of maternal diet may have minimal impact on offspring body weight in this well-nourished population,” the investigators said.