Prenatal acetaminophen use occurred in 55% of the mothers in the study, the researchers wrote, but such use was not associated with BMI and waist circumference in all children, whereas girls aged 7 years and boys of any age were not affected in terms of overweight status. According to the researchers, girls aged 11 years who had mothers who used acetaminophen while pregnant were 10% more likely to be overweight (RR = 1.1; 95% CI, 0.97-1.24) compared with girls whose mothers did not use acetaminophen. In addition, the researchers noted that using acetaminophen during each trimester increased the odds (RR = 1.31; 95% CI, 1.1-1.56) for girls aged 11 years.
“The positive association observed for girls at 11 years might indicate a sex-hormone-specific mechanism of the exposures, but it could also be explained by the timing of pubertal growth and outcome measures in our study,” the researchers wrote. “Studies with longer follow-up time are needed to evaluate whether the estimated sex-specific exposure effects persist into older ages.”