Phthalate exposure during second and third trimester of pregnancy may impact fetal growth and development: Study

The key findings of the study were:

Other than monobenzyl phthalate (MBzP), detected in 25%-33% of samples, other metabolites were found in over 86% of urine samples, indicating widespread exposure to DEP, DBP, and DEHP.

• The phthalate exposure levels in this cohort were significantly higher than those reported in other countries.

• The levels of phthalate metabolites changed across trimesters, suggesting changing exposures and metabolic changes during pregnancy.

• There were significant linear trends for FT4, TSH, and to some degree TT3, across quartiles of specific phthalate metabolites. In the highest quartiles:

• A 2%-3.7% increase in FT4 levels associated with MEP, MECPP, MEHHP, and a number of sums of metabolites.

• Significantly, it contributes to a rise in TSH levels for all phthalate metabolites with the exception of MEHHP.

• This corresponds to an increase of 2.2% for TT3 with MEP, and a decrease of 2.7% with ΣDBP.

• Higher TSH/FT4 ratios were found with higher quartiles of the following specific phthalate metabolites: MEP, MiBP, MnBP, ∑7PAE, ∑DBP, and ∑LMW.

On the basis of these findings, inference can be made that the exposure to phthalate in utero is associated with changes in maternal thyroid hormone concentrations. This research underlines that during pregnancy, phthalate exposure should be monitored because of its possible disturbances in thyroid hormone levels, very critical for fetal development. The result reiterates the need for further confirmation of the present findings and exploring mechanisms through which phthalates may influence the action of thyroid.

Reference:

Al-Saleh, I., Elkhatib, R., Alghamdi, R., Alrushud, N., Alnuwaysir, H., Alnemer, M., Aldhalaan, H., & Shoukri, M. (2024). Phthalate exposure during pregnancy and its association with thyroid hormones: A prospective cohort study. International Journal of Hygiene and Environmental Health, 261(114421), 114421. https://doi.org/10.1016/j.ijheh.2024.114421