Thyroid Function in Male Infertility

Last, the use of ICSI for male factor infertility and the number of embryos transferred could affect the outcomes. Thus, all these factors may have influenced the interpretation of the results, making the final medical decision often challenging to make. Thyroid disorders are mainly categorized into two groups; hypothyroidism and hyperthyroidism. As explained earlier thyroid hormones are important regulator of male reproductive function so any alterations in their serum levels have profound effects on male reproduction. The importance of thyroid hormones in the female reproductive system has been highlighted since the evidence of synthroid afib TSH and thyroid hormone receptors (TR-a1 and TR-b1) on ovarian and oocytes surface 15, so its role in folliculogenesis, fertilization, embryogenesis, and in implantation, and maintaining pregnancy is inevitable. In this regard, in vitro studies suggest that thyroid hormones promote FSH-induced preantral follicle growth, activating the protein kinase B (Akt) pathway 16.

Studies assessing the role of hypo- and hyperthyroidism in male infertility have also been conducted in human subjects. Hypothyroidism may result in a decrease in the sex hormone binding globulin (SHBG) levels and a decrease in total serum testosterone levels, as well as a decrease in the LH and the follicle stimulating hormone (FSH) levels (21). In cases of prolonged pre-pubertal hypothyroidism due to drop in LH and FSH levels, the Leydig and Sertoli cells, respectively are less stimulated to differentiate into mature cells, negatively affecting spermatogenesis. This increases the number of cells in the testes but decreases the number of mature cells.

Poppe et al. in 2018 investigated the impact of TAI on pregnancy outcomes in infertile women undergoing ICSI treatment, excluding IVF or IUI cycles, accounting for 4 studies for a total of 1855 ICSI cycles (of them, 290 with TAI) reporting no increased risk of early miscarriage 62. A meta-analysis investigating the effect of levothyroxine treatment in TAI-positive women undergoing ART denied any positive impact on that the miscarriage rate; however, levothyroxine decreased the miscarriage rate if subclinical hypothyroidism was present 63 suggesting that this condition per se may be detrimental 9, 64. Specific information regarding the effect of thyroid function on controlled ovarian hyperstimulation (COH) is limited, mainly due to the absence of randomized controlled trials. When it comes to male fertility, a range of factors contribute to overall reproductive health, and one that often goes under the radar is thyroid function. The thyroid gland, known for regulating metabolism and energy, also plays a crucial role in the male reproductive system. Proper thyroid function ensures optimal sperm production and sperm quality, while imbalances in thyroid hormone levels—whether too high or too low—can lead to fertility issues.

Additionally, studies disagree on whether there is a relationship between the severity of ED and the severity of hormone derangement. Other sexual dysfunctions such as DE and HSD are less researched and require further investigation to reach a meaningful consensus on their relationship with hyperthyroidism. Thyroid hormones increase hepatic SHBG production, which is also regulated by hepatocyte nuclear factor-4a (HNF-4a) in response to changes in the metabolic state of the liver 23.

Therefore, LT4 significantly reduced sperm necrosis and lipid peroxidation ameliorating chromatin compactness.
If you develop hypothyroidism you may feel tired, lethargic, depressed and cold, and your skin may be dry.
Regular monitoring through a thyroid blood test can aid in early detection and effective management, ensuring better reproductive health outcomes.
Thyroid disorders are mainly categorized into two groups; hypothyroidism and hyperthyroidism.
However, more research is needed to determine exactly how normalization of thyroid hormone levels affects other aspects of sexual functioning.

Women

However, your levothyroxine treatment should be adjusted to normalise your thyroid function as soon as possible. Review of the literature examining effects of hypo- and hyperthyroidism on sexual function. Thyroid hormones and hormone receptors also regulate the endometrium receptivity, which is the stage where all the actors, including thyroid hormones, cooperate to prepare and allow the implantation window of the blastocyst, with variations during the menstrual cycle 19, 20. If you have had postpartum thyroiditis, even though you have made a full recovery initially, it is recommended that you have your thyroid function checked before you try to conceive again and at the start of your next pregnancy to ensure that you have not developed hypothyroidism. There is an up to 50% risk that you develop a recurrence of postpartum thyroiditis in subsequent pregnancies.

Thyroid Hormones and Spermatozoa: In Vitro Effects on Sperm Mitochondria, Viability and DNA Integrity

It is likely that you will require higher doses of levothyroxine during pregnancy, especially during the first 20 weeks, to provide sufficient supply of thyroid hormones to the baby. As soon as you know you are pregnant, it is generally recommended that your levothyroxine is increased immediately, usually by mcg daily. We recommend that you double your current dose on two days each week (e.g. every Saturday and Sunday). You should then contact your GP and arrange to have a thyroid blood test so that more targeted adjustments can be made if required. Women who have previously had Graves’ disease (but not had thyroid surgery or radioiodine) may relapse at any stage, but the risk rises after giving birth and remains high for one year.

This review summarizes the normal thyroid hormone regulation of semen quality, provides an update on human and animal studies on thyroid disorders and altered semen quality and also elucidates the possible mechanism of hypothyroidism and hyperthyroidism-induced alterations in semen quality.
If you have been treated for Graves’ disease with radioactive iodine or surgery in the past, or need antithyroid drugs during pregnancy, you may have Graves’ antibodies (also known as TSH receptor antibodies (TRAb)), which can cross the placenta.
In an effort to determine the constellation of factors responsible for sexual dysfunction, the effect of thyroid hormone derangements has been of recent interest.
Interestingly, the beneficial impact may be only for those conceiving naturally, as the miscarriage rate was unchanged in those undergoing ART 63.
Women with raised (or positive) anti-thyroid peroxidase (TPO) antibodies, which indicate a degree of thyroid autoimmunity, are at increased risk of having a miscarriage.

The Role of the The Thyroid Gland In Male Reproduction

LT4 significantly increased the percentage of spermatozoa with high mitochondrial membrane potential (MMP), decreased the percentage of spermatozoa with low MMP and increased sperm motility already at a concentration of 0.9 pmol L-1.
Even TSH levels lower than 0.1 mU/L may occur approximately in 5% of women by week 11 of pregnancy 9.
In both hyper- and hypothyroid men, treatment of thyroid disorder at least partially reverses sexual dysfunction.
In these hypothyroid patients the sexual behavior improved with restoration of euthyroid status.2 The exact cause of sexual dysfunction in hypothyroidism is not clear.
Consequently, thyroid hormones impairment could affect markers of ovarian reserve, including anti-Mullerian hormone (AMH) 18.

As research continues, scientists are discovering more about the link between the endocrine system, thyroid health and male fertility. While current treatments for thyroid-related fertility issues are effective, future studies may reveal new ways to enhance fertility outcomes. Ongoing research will likely focus on how specific thyroid-related interventions improve sperm production, and whether routine thyroid function tests should be included in the diagnostic workup for male infertility. Around 1 in 1,000 men experience hyperthyroidism, and hypothyroidism affects about 1 in 100.

Role of TSH vs thyroid hormones

The results of this in vitro study could have a clinical application in patients with idiopathic infertility, clarifying the role of thyroid function on male fertility. The thyroid gland is responsible for secreting hormones that regulate metabolism, growth and development. Among these hormones, thyroxine (T4) and triiodothyronine (T3) are essential for maintaining normal reproductive function.

Thyroid dysfunction and semen quality

Reduction in sperm vitality may result from increased oxidative stress and reduced antioxidant capacity in reduced thyroid hormone actions. The primary study examining sexual dysfunction in women after thyroid hormone normalization is by Oppo et al. The authors found that after 3 months of treatment, desire, satisfaction and pain domain scores of the FSFI increased to control group levels in both hypo and hyperthyroid women. However, the hypothyroid group had a significant increase from baseline while the hyperthyroid group did not. Notably, the lack of orgasm remained an issue in both hypo- and hyperthyroid groups, suggesting lack of reversibility of this symptom of FSD. Most studies demonstrate that hypothyroid and hyperthyroid men have increased rates of sexual dysfunction, including erectile dysfunction (ED) in hypothyroid men.

Thus, in patients with hypothyroidism, increased testicular size is observed along with a significant drop in mature germ cells within the seminiferous tubules (22, 23). Fortunately, hypothyroidism is very rare in males with an occurrence rate of only 0.1% in the general population (21). Among the studies on human subjects, Corrales Hernandez et al. (24) analyzed blood and semen samples of patients with primary hypothyroidism (24).