Exposure profiles to Phthalates and their impacts on thyroid hormones in pregnant women

Purpose This research aims to assess the exposure of pregnant women to Phthalates and to investigate the relationship between plasma levels of thyroid hormones and urinary concentrations of Phthalates. It also explores potential exposure sources and examines the links between surrounding products and exposure profiles in these women. Method This was a descriptive, transversal, and multicentre study carried out on a population of 384 pregnant women living in Algiers. Thyroid hormones (TSH, FT3, and FT4,) were measured by electrochemiluminescence. Phthalates (MEP, MEHP, and MnBP) were detected and assessed by LC-MS/MS. Results Phthalates were detected in most urine samples (97.4%, 95.58%, and 92.97% for MEP, MEHP, and MnBP, respectively). Mean concentrations of MEP, MEHP, and MnBP were 83.496  ±  89.133, 37.915  ±  41.082 and 44.635  ±  48.169 µg/g creatinine, respectively. Significant positive associations were identified between urinary concentrations of MnBP and FT3 levels (β = 0.002; P = 0.018). Significant associations were found between the consumption of bagged milk and all three Phthalate metabolites. High urinary concentrations of MEP and MEHP were found in women living industrial factories, while elevated urinary concentrations of MnBP were found in women residing in urban areas. Additionally, this study revealed that women who paid attention to the ingredients in their care products have lower urinary concentrations of MnBP. Conclusion This study highlights the harmful effect of Phthalates on thyroid hormone levels during pregnancy. These findings lead us to investigate the potential effects of these hormonal changes on pregnant women, and to put proper regulations on the potential sources of exposure.