A Comprehensive Systematic Review of the Impact of Variations in Serum FT3, FT4 and TSH Levels on Pregnant and Non-Pregnant Women
Keywords:
FT3, FT4, TSH, Pregnant, Non-Pregnant, ReviewAbstract
Thyroid hormones such as free thyroxine (FT4), free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH) play an important role in women's metabolism, reproduction, and overall health. This systematic review aims at exploring how changes in serum FT3, FT4 and TSH levels impact on health outcomes such as pregnancy issues, fertility and metabolic diseases in both pregnant and non-pregnant women. A systematic search was carried out to identify research articles published in English and Arabic from 2010 to 2025, using databases like PubMed, Scopus, Web of Science, and Google Scholar. Inclusion criteria were studies that evaluated thyroid function in females of reproductive age; exclusion criteria were studies of males or any thyroid condition other than thyroid function. Results indicate that there are physiologic changes within a woman's thyroid hormone levels throughout the course of her pregnancy. In the first trimester, her TSH drops and her FT4 levels rise, which increases the chance of miscarriage and hypothyroidism causes foetal growth restriction. In hyperthyroidism there is an association with low birth weight and prenatal hypertension. One of the symptoms for women who are not pregnant and suffer from thyroid dysfunction is infertility, irregular periods, and some other persistent metabolic issues. Foetal thyroid hormone needs put pregnant women at a higher risk, but even women who aren't pregnant run the risk of experiencing long-term health effects. The best results can be achieved with routine thyroid screening, which is especially important in the first trimester of pregnancy. Awareness creation on thyroid health and setting up population specific reference range is recommended. Future research should also gather regional data and pursue long-term studies of reproductive and general health, especially in Arab communities, to further understand how to improve reproductive and overall health.
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