Effects of Exposure to Chromium During Pregnancy on Fetal Growth and a Possible Sex-Dependent Response: Results of Cross-sectional Study

Abstract

Fetal growth restriction (FGR) or small for gestational age (SGA) is a serious birth outcome affected by environmental factors. Animal studies have shown that prenatal chromium (Cr) exposure leads to intrauterine growth restriction and reduced birth weight in fetal rats. However, evidence remains limited in human studies. Our study aimed to examine the association between maternal urinary Cr levels during pregnancy and also investigated possible sex-dependent response. Our cross-sectional study included 1,220 women with singleton pregnancies in the third trimester (38.31 ± 1.82 weeks). Maternal urinary Cr levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Subsequently, the relationship between Cr exposure and SGA was evaluated using logistic regression analysis. Our investigation has found that the incidence of SGA was 13.2% in the high-exposure group (urinary Cr ≥ 14.76 µg/L; n = 305) compared to 4.6% in the low-exposure group (urinary Cr < 14.76 µg/L; n = 915; P = 0.004). The risk of SGA increased 6.2-fold for each unit increase in the normalized Cr levels in the newborns when the maternal urinary Cr concentration was > 26.15 µg/L. After adjusting for covariates, disparities were observed in the urinary Cr exposure among SGA infants based on their sex. Specifically, male infants with high Cr exposure had a higher risk of SGA than those with low exposure (odds ratio, 3.2; 95% confidence interval: 1.73, 6.04). Study found that maternal Cr exposure can affect SGA. Moreover, sex-specific implications of Cr on fetal development were observed, with male infants showing a higher susceptibility than the female.

Keywords: Chromium; Fetal growth restriction; Sex differences; Small for gestational age.