Impact of Variations in Serum FT3, FT4, and TSH Levels on Pregnant and Non-Pregnant Women: A Comprehensive Systematic Review
Keywords:
FT3, FT4, TSH, Pregnant, Non-Pregnant, ReviewAbstract
Thyroid hormones, including free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH), are essential for regulating metabolism, reproduction, and overall health in women. This systematic review examines the impact of variations in serum FT3, FT4, and TSH levels on pregnant and non-pregnant women, focusing on health outcomes such as fertility, pregnancy complications, and metabolic disorders. A systematic methodology was employed, searching databases including PubMed, Scopus, Web of Science, and Google Scholar for studies published in English and Arabic between 2010 and 2025. Studies addressing thyroid function in women of reproductive age were included, while those focusing solely on non-thyroid diseases or men were excluded. Findings reveal that pregnant women experience physiological shifts in thyroid hormone levels, with decreased TSH and elevated FT4 in early pregnancy, increasing risks of miscarriage and fetal growth restriction in hypothyroidism. Hyperthyroidism is linked to gestational hypertension and low birth weight. In non-pregnant women, thyroid dysfunction contributes to infertility, menstrual irregularities, and chronic metabolic issues. Pregnant women face heightened vulnerability due to fetal thyroid hormone demands, while non-pregnant women may experience long-term health impacts. Routine thyroid screening, particularly in early pregnancy, is critical for optimizing outcomes. Population-specific reference ranges and increased awareness of thyroid health are recommended. Future research should focus on longitudinal studies and regional data, especially in Arab populations, to inform targeted interventions for improved reproductive and general health.
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