Association between prenatal antibiotics exposure and measures of fetal growth: A repeated-measure study

The abuse of antibiotics in animal husbandry has brought many public health problems, among which the passive use of antibiotics caused by eating food containing residual antibiotics has attracted the most attention. However, few studies have examined the possible adverse effects of prenatal antibiotics exposure on fetal growth and development. In this study, we investigated the associations between prenatal antibiotics exposure and measures of fetal growth. A total of 429 mother-newborn pairs from a birth cohort were enrolled and spot urine samples (N = 1287) were collected during each trimester of pregnancy. Sixteen antibiotics from 7 categories, were selected for the determination of the targeted antibiotics in maternal urines by UHPLC-MS/MS. Fetal growth indicators including newborn birth weight, birth length and gestational age (GA), were obtained from medical record. Sixteen antibiotics were found in 92.3% of the urine samples with detection frequencies ranging from 0.3% to 41.3%. Among the 16 antibiotics detected, we found that the exposure level of ciprofloxacin in the first trimester of pregnancy was negatively correlated with GA (β = -0.17 day, 95% CI, -0.32 to -0.02 day), which would increase the risk of preterm birth (OR=1.05, 95% CI, 1.00, 1.09). The exposure level of norfloxacin in the second trimester of pregnancy was negatively correlated with fetal birth weight (β = -17.56 g, 95% CI, -31.13 to -3.99 g) and birth length (β = -0.05 cm, 95% CI, -0.08 to -0.02 cm), and the exposure level of sulfamethoxazole in the third trimester of pregnancy was negatively correlated with fetal birth length (β = -0.15 cm, 95% CI, -0.29 to -0.02 cm). Our findings suggest that prenatal exposure to norfloxacin and sulfamethoxazole may adversely affect fetal growth and development.