Maternal healthy lifestyle during early pregnancy and offspring birthweight: differences by offspring sex

Abstract

Purpose: Individual maternal lifestyle factors during pregnancy have been associated with offspring birthweight; however, associations of combined lifestyle factors with birthweight and potential differences by offspring sex have not been examined.

Materials and methods: Participants (N = 2924) were identified from a pregnancy cohort in Washington state. Lifestyle factors during early pregnancy were dichotomized based on Alternate Healthy Eating Index score ≥62, leisure time physical activity (LTPA) ≥ 150 min/week, not smoking during pregnancy and Perceived Stress Scale score ≤3, then combined into a lifestyle score (0–4). Regression models were run overall and stratified by offspring sex, prepregnancy overweight/obese (BMI ≥25 kg/m²) and prepregnancy LTPA.

Results: Overall, 20% of participants had healthy diet, 95% were nonsmokers, 55% had low stress levels, and 66% were physically active. Lifestyle score was not associated with birthweight (β = 3.3 g; 95% CI: −14.5, 21.0); however, associations differed by offspring sex (p = .009). For each unit increase in lifestyle score, there was a suggested 22.4 g higher birthweight (95% CI: −2.7, 47.6) among males and 14.6 g lower birthweight (95% CI: −39.9, 10.7) among females. Prepregnancy BMI and LTPA did not modify associations.

Conclusions: Healthy lifestyle score in early pregnancy may be associated with greater birthweight among male offspring, but lower birthweight among female offspring.

Keywords:

• Birthweight
• diet
• lifestyle
• physical activity
• physiological stress
• pregnancy
• smoking

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

This work was supported by the National Institutes of Health under Grant T32 HD052462, R01HD-32562, and K01HL103174.