Introduction
Thyroid hormones play a pivotal role in regulating reproductive function in women. Thyroid disorders such as hypothyroidism and hyperthyroidism can significantly impact this system, leading to alterations in menstrual cycles, fertility, pregnancy, and associated complications.
Hypothyroidism and the Reproductive System
Hypothyroidism is often linked to menstrual cycle disturbances, including anovulatory cycles, menorrhagia (excessive menstrual bleeding), and infertility. Reduced thyroid hormone levels commonly affect ovulation, interfering with oocyte maturation and leading to anovulation.
Women with hypothyroidism have an increased risk of miscarriage during pregnancy and complications such as preeclampsia and premature birth. They may also face a higher risk of hemorrhage during childbirth and give birth to low birth weight infants due to hormonal impacts on fetal development.
Hyperthyroidism and the Reproductive System
In cases of hyperthyroidism, elevated levels of thyroid hormones can result in menstrual cycle irregularities. Women may experience hypomenorrhea (reduced menstrual flow) to amenorrhea (complete absence of menstruation), and these changes can influence fertility. It’s important to note that decreased fertility can be associated with elevated thyroid hormone levels in hyperthyroidism.
Involved Mechanisms
The mechanisms by which hypo- and hyperthyroidism affect the female reproductive system may involve disruptions in the hypothalamic-pituitary-thyroid axis and hormonal feedback. Hormonal imbalance directly influences the production and regulation of female sex hormones, compromising ovarian function and the menstrual cycle.
Conclusion
Hypo- and hyperthyroidism can significantly impact the female reproductive system, affecting menstrual cycles, fertility, pregnancy, and fetal health. It’s crucial for women diagnosed with thyroid disorders to receive proper monitoring and treatment to minimize the negative impact on reproductive health and avoid associated complications.
References
- Ross DS, Burch HB, Cooper DS, Greenlee MC, Laurberg P, Maia AL, et al. “2016 American Thyroid Association Guidelines for Diagnosis and Management of Hypert- hyroidism and Other Causes of Thyrotoxicosis.” Thyroid. 2016;26(10):1343-1421. doi: 10.1089/thy.2016.0229.
- Cooper DS, Ladenson PW. “The Thyroid Gland.” In: Gardner D.G., Shoback Dolores, Greenspan’s Basic & Clinical Endocrinology. McGraw-Hill Education; 2018. p. 171-238.
- Gargallo Fernández M. “Hyperthyroidism and pregnancy.” Endocrinol Nutr. 2013;60(9):535-43. English, Spanish. doi: 10.1016/j.endonu.2012.11.006.