Longitudinal assessment of prenatal phthalate exposure on serum and cord thyroid hormones homeostasis during pregnancy - Tainan birth cohort study (TBCS)
Journal
Science of The Total Environment
Journal Volume
619-620
Start Page
1058-1065
ISSN
0048-9697
Date Issued
2018-04
Author(s)
Abstract
An increasing number of studies have revealed that phthalate exposure alters thyroid hormone homeostasis in the general population, but there is insufficient evidence of the effect of longitudinal maternal phthalate exposure on maternal and fetal thyroid hormones during pregnancy. We longitudinally assessed the effect of prenatal phthalate exposure in pregnant women on umbilical cord and maternal thyroid hormones at three trimesters during pregnancy. We recruited 98 pregnant women and collected urine and blood samples at three trimesters in an obstetrics clinic in Southern Taiwan from 2013 to 2014. We analyzed the concentrations of 11 urinary phthalate metabolites, including monoethylhexyl phthalate, mono-(2-ethyl-5-oxo-hexyl) phthalate (MEOHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-n-butyl phthalate, monoisobutyl phthalate (MiBP), monoethyl phthalate (MEP), using online liquid chromatography-tandem mass spectrometry. The cord and maternal serum levels of thyroxine (T), free T, triiodothyronine (T), thyroid-stimulating hormone (TSH), and thyroxine-binding globulin were measured using an electrochemiluminescence immunoassay. A mixed-model analysis was utilized to assess the effect of longitudinal phthalate exposure on thyroid hormones and adjusted for significant covariates. We found that urinary MiBP (β=-0.065, 95% confidence interval (CI): -0.124, -0.005), and MEOHP (β=-0.083, 95% CI: -0.157, -0.009) were significantly negatively associated with serum TSH. Urinary MECPP was inversely related to serum T (β=-0.027, 95% CI: -0.047, -0.006). Urinary MEP (β=0.014, 95% CI: -0.001, 0.028) and MiBP (β=0.033, 95% CI: 0.018, 0.049) were positively related to free T. We found that cord serum T (β=0.067, 95% CI: 0.003, 0.131) and free T (β=0.031, 95% CI: 0.001, 0.062) levels had significant positive associations with maternal ΣDBPm levels at the second trimester. We concluded that different phthalates exposure windows during gestation may alter cord and serum thyroid hormone homoeostasis.
Subjects
Cord blood
Phthalate metabolites
Pregnant women
Taiwanese
Thyroid hormones
Urine
Publisher
Elsevier BV
Type
journal article