Sex-specific associations between prenatal antibiotics exposure and offspring's body mass index

Objective Animal studies and epidemiological studies have shown that there is potential sex-specific sensitivity to the intrauterine environment in relation to the developmental programming of obesity. The objective of this study was to assess the sex-specific association between prenatal antibiotics exposure and body mass index (BMI) in offspring from 1 to 4 years. Methods A total of 10,163 mother-child pairs from the Medical Birth Registry in Xiamen, China, were included in this prospective cohort study. Data on prenatal antibiotics exposure were collected from the prescription database. Results A total of 4909 (48.3%) offspring had prenatal antibiotics exposure. The associations between prenatal antibiotics exposure and offspring's BMI were significantly different among female offspring and male offspring (Pfor interaction: 0.034 at 1 year of age; 0.033 at 2 years of age; 0.020 at 3 years of age; and 0.021 at 4 years of age). In female offspring, prenatal antibiotic use was significantly associated with a higher BMIZ-score from 1 to 4 years old (difference in BMIZ-score: 0.11 [95% CI: 0.05-0.17] at 1 years of age; 0.10 [95% CI: 0.05-0.16] at 2 years of age; 0.14 [95% CI: 0.09-0.21] at 3 years of age; and 0.13 [95% CI: 0.07-0.19] at 4 years of age) after adjustment for confounder. Prenatal antibiotics use was not associated with offspring BMIZ-score from 1 to 4 years in male offspring. Conclusions The association of prenatal antibiotics exposure and BMIZ-score from 1 to 4 years old may differ by sex of offspring.