Thyroid disease is a common health problem that can affect both men and women. And if left untreated it can affect the overall health including the reproductive health. Both hyperthyroidism (high levels of thyroid hormones) and hypothyroidism (low levels of thyroid hormones) have a significant effect on estrogen and androgen (sex hormones of women and men, respectively) metabolism, which affects menstruation, hormone production, and fertility.
Hence, if you are already diagnosed with thyroid disease, it is important to take medicines without fail and keep the levels under control as any imbalance can impact fertility in both men and women. Here’s how thyroid dysfunction can lead to infertility.
Thyroid and infertility in women
Excess or low levels of thyroid hormones not only impacts the functioning of other hormones in the body but also impacts menstruation, ovulation, and pregnancy.
Menstruation and hormones: Hyperthyroidism is characterized by infrequent or scanty menstruation or amenorrhea. This is because, thyroid hormones are vital for the production of female hormones such as estrogen, progesterone, and prolactin.
Low levels of thyroid hormones can impair the functioning of these hormones, which in turn can affect menstruation. Moreover, an imbalance in the thyroid hormones can cause an excess production of prolactin, a hormone which promotes lactation, which can cause irregular or absent periods.
Quality of the egg: The luteinizing hormone (LH) stimulates the ovaries to produce hormones which are needed for ovulation. But low levels of thyroid hormones affect the functioning of the LH, which further interferes with the ovulation process and thus impacts pregnancy. Moreover, hypothyroidism leads to less production of progesterone, a hormone which is needed for the development of the egg. Low progesterone levels lead to poor egg quality, which further interferes with fertility in women.
Fertilization and implantation of the egg: An imbalance in the thyroid hormone levels can lead to a short luteal phase, which affects the quality of the egg released for fertilization. It also impairs the implantation of the fertilized egg. The failure to sustain the egg can lead to a miscarriage.
Thyroid and infertility in men
Excess of thyroid hormone, also known as hyperthyroidism, can affect sperm motility. It can also cause structural abnormalities in the sperm and also lead to erectile dysfunction.
Sperm production: The cells in the male reproductive organ that provide nutrition to the sperm cells have thyroid hormone receptors. An imbalance in the thyroid hormones can directly affect the production of the sperm. And decreased sperm count can increase the risk of infertility.
Testosterone production: Low levels of thyroid hormone can decrease the production of testosterone, which plays a key role in the functioning of the testes where the sperm is produced. Hence, low levels of testosterone can lead to low sperm count, reduced sperm motility and low libido, which in turn affects fertility.
The thyroxine treatment for hypothyroidism, as advised by your doctor, can help restore normal thyroid functioning and lead to normalization of menstrual pattern and reverse hormonal changes, thereby helping in ovulation and conception. The same rule applies to the treatment of infertility in men due to thyroid dysfunction.
Hence, in addition to ensuring regular intake of prescribed medicines, supplements and diet modifications, it is also important to undergo appropriate infertility tests as suggested by your clinician, if planning for pregnancy.
Recommended Reads:
Hypothyroidism: Are You Making These Common Mistakes With Your Medication?
What Causes Infertility In Men And How Is It Treated?
References:
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Kumar A, Shekhar S, Dhole B. Thyroid and male reproduction. Indian J Endocrinol Metab. 2014 Jan;18(1):23-31.
Rajender S, Monica MG, Walter L, Agarwal A. Thyroid, spermatogenesis, and male infertility. Front Biosci (Elite Ed). 2011 Jun 1;3:843-55.
Gude D. Thyroid and its indispensability in fertility. J Hum Reprod Sci 2011;4:59-60