Thyroid impairment and male fertility: a narrative review of literature

Figures & data

Figure 1. Diagram of the screening and selection process.

Table 1. Summary of clinical studies and case reports about thyroid function and male fertility in animals in vivo.

Author, date	Study design	Animal model	Outcome
[40]	Case–control	Colony bred albino hypothyroid rats	Hypothyroidism did not evoke any significant change in testes weight, while the weights of seminal vesicle and ventral prostate were greater than controls. No alteration in spermatogenesis and no morphological changes of Leyding cells. Diminished libido was observed in hypothyroid rats and their fertility was reduced, with a diminished trend in litter size.
[70]	Observational	Long-Evans rats	Treatment with T3 led to no change in either serum LH or FSH levels
[71]	Case–control	10 hypothyroid Wistar rats	Hypothyroidism did not affect testicular function and weight of testicles, ventral prostate, and seminal vesicles.
[72]	Observational	Long-Evans rats	Treatment with T3 led to no change in either serum LH or FSH levels
[22]	Case–control	Sprague-Dawley male rats	Hypothyroidism results in decreased release of LH and FSH in rats with intact gonads, and in increased release of LH and FSH in castrate rats. Administration of a replacement dose of L-T4 can restore LH and FSH release to normal in rats with intact gonads, and to castration levels in castrate rats. Higher weight of seminal vesicles in hypothyroid rats.
[30]	Case–control	Hypothyroid Wistar rats	Reduced weight of seminal vesicles and ventral prostate and normal serum levels of testosterone, LH and FSH.
[43]	Case–control	Sprague-Dawley hyperthyroid rats	Hyperthyroidism leaded to a fall in FSH levels either via direct pituitary suppression or via accelerated FSH metabolism; no changes in E2 and testosterone, non-significant reduction of LH. In vitro studies showed an increased testicular testosterone synthesis and intratesticular stimulation of 17 beta-hydroxysteroid dehydrogenases.
[24]	Case–control	56 adult male hypothyroid Lewis rats (treated with PTU).	Pituitary concentrations of TSH, PRL and FSH were significantly reduced by the treatment with PTU. There was also a slight, but insignificant reduction of pituitary concentrations of LH. Those alterations were restored after treatment with thyroid hormones.
[73]	Case–control	Infertile and hypothyroid mice	Hypothyroidism was not associated with a reduction of spermatogenesis or testosterone secretion; etiology of infertility was unknown.
[25]	Case–control	54 hypothyroid Wistar rats	Reduced weight of seminal vesicles and ventral prostate and serum levels of testosterone, normalized after L-T4 replacement.
[74]	Case–control	90 hyperthyroid Wistar rats	Reduced serum levels of LH, FSH and testosterone in hyperthyroid rats.
[33]	Observational	Hypothyroid immature male rats	Thyroidectomy inhibited gametogenesis and development of the Leydig cell; however, the effects could be reversed by T4
[23]	Case–control	12 hypothyroid Wistar adult rats, among whom 6 T3 treated	Hypothyroidism decreases weight of testicles and sex accessory glands, serum levels of LH and testosterone. T3 replacement normalized serum hormonal levels but not the structural changes.
[75]	Case–control	13 hypothyroid rats	In hypothyroid rats seminiferous tubules were smaller in size and contained fewer spermatogonia, spermatocytes, spermatids and spermatozoa. T4 brought about an increase in cell counts of the seminiferous tubules and in sperm counts in both groups.
[76]	Case–control	15 hypothyroid rats	Hypothyroidism did not affect sexual behavior or cause infertility; hypothyroid rats initiated first pregnancy later than controls.
[77]	Case–control	18 hypothyroid Sprague-Dawley adult rats	Hypothyroidism did not affect testis weights, serum levels of testosterone, or the structure of seminiferous tubules.
[26]	Case–control	22 hypothyroid Wistar adult rats, among whom 11 T3 treated	Hypothyroidism decreases in vitro production on testosterone and its precursors but no signification variation in testis weight. T3 treatment partially restores in vitro testosterone production.
[78]	Case–control	Male Wistar rats	In the adult testis, both in vivo and in vitro treatments with thyroid hormone did not induce morphological modifications. A slight, but significative increase of FSH levels was found compared to controls in T3 treated animals
[35]	Case–control	60 infertile hypothyroid rdw rats	L-T4 treatment induced a partial reversion of the impaired sexual behavior and a complete reversion of fertility of epididymal sperm
[27]	Case–control	Rats with transient and persistent hypothyroidism	Persistent hypothyroidism diminishes the bioavailability of androgens and oestrogens, while transient hypothyroidism enhances it.
[32]	Case–control	Hypothyroid rats	Hypothyroidism resulted in a reduction in body weight, seminal vesicle and ventral prostate gland. A further decrease in the weight of seminal vesicle was recorded following administration of T3 to hypothyroid rats.
[31]	Case–control	Congenital hypothyroid mutant male rdw rats	Even low levels of circulating thyroid hormone stimulate the development of testes probably through Sertoli cells, resulting in the enlarged adult testes without fertility. Thyroid hormone plays a pivotal role in restoring mating activity, probably through FSH-mediated action towards adulthood.
[44]	Case–control	Male Wistar rats	In hyperthyroid rats, testes maturation and intense protein synthesis and processing were found. An increase in mitochondrial reactive oxygen species generation, underlying cellular oxidative damage, is a side effect of hyperthyroid-induced biochemical changes by which rat testis increase their metabolic capacity
[37]	Case–control	Hypothyroid adult male Wistar rats	Hypothyroid condition disturbed intra-mitochondrial thiol redox status leading to testicular dysfunction. Hypothyroidism-induced oxidative stress condition could not be reversed with T3 treatment.
[39]	Case–control	Hypothyroid male albino rats	Plasma total homocysteine, total NO metabolites, malondialdehyde and GSSG/GSH ratio quantified by HPLC increased in hypothyroid rats as compared to controls. These biochemical alterations at least in part disrupted spermatogenesis in these experimental models
[28]	Case–control	Hypothyroid rats	Hypothyroidism in adult male rats altered posttranscriptional mechanisms of LH synthesis and probably had a direct effect on testicular function.
[42]	Case–control	40 adult male Wistar rats rendered hyperthyroid with L-T4	Induction of hyperthyroidism cause a decrease in absolute genital sex organs weight, a significant decline in serum levels of LH, FSH and testosterone along with significant increase in serum estradiol level. Hypermetabolic state induced by excess level of thyroid hormones may be a causative factor for the impairment of testicular physiology as a consequence of oxidative stress
[29]	Case–control	20 hypothyroid (PTU treatment) Wistar adult rats, 20 hyperthyroid (L-T4 treatment) Wistar adult rats	Hypo- and hyperthyroidism lowered genital sex organs weight, sperm count and motility, serum levels of LH, FSH and testosterone; they increased serum E2 level, testicular oxidative stress, DNA damage and apoptotic markers. Data were backed by morphometric and histopathologic studies.
[36]	Case–control	10 hypothyroid Wistar rats, 10 hyperthyroid Wistar adult rats	Hypothyroidism decreased the total and daily sperm productions and increased the sperm transit time through the epididymis; the sperm functionality was reduced in both thyroid dysfunctions.
[34]	Case–control	12-15 male rats with hypothyroidism and 12-15 with hypothyroidism and diabetes	Diabetes combined with hypothyroidism inhibits spermatogenesis and decreased sperm motility. Hypothyroidism inhibited seminiferous tubules development in both immature and prepubertal mice.
[38]	Case–control	Euthyroid, hypothyroid, hyperthyroid Wistar rats	There is a correlation between thyroid disorders and impaired antioxidant defence mechanism, resulting in reproductive dysfunctions, as infertility, mainly observed in hypothyroidism.

T4: thyroxine; T3: thyronine; PTU: propylthiouracil; LH: luteinizing hormone; FSH: follicle stimulating hormone; E2: estradiol

Table 2. Summary of clinical studies and case reports about thyroid function and male fertility in human.

Author, date	Study design	Patients	Outcome
[49]	Case series	Six adult male patients with myxedema of severe degree and long duration	Prepuberal onset of hypothyroidism was associated with delayed testicular maturation and involution of adult characteristics
[54]	Case series	Five men with primary myxedema, 30–64 years old	Normal sperm in three patients, two showed losses in motility that in one patient improve after triiodothyronine administration
[63]	Case series	Three young men with hyperthyroidism	Two patients had marked oligospermia with decreased motility, and the third patient had a borderline low sperm count associated with decreased motility.
[79]	Observational study	Seven consecutive men with thyrotoxicosis due to Graves’ disease	Men with hyperthyroidism have partial Leydig cell failure and impairment of spermatogenesis.
[45]	Observational retrospective	Eight men with primary hypothyroidism (five AITD related, and three amiodarone inducted), 37–77 years old	Hypergonadotropic state in five patients and hypogonadotropic hypogonadism in three patients, low testosterone levels in four patients
[64]	Observational prospective	8 hyperthyroid men given two identical intravenous GnRH tests	Chronic thyroid hormone excess makes the pituitary gonadotrophs “hypersensitive" to exogenous GnRH.
[55]	Observational prospective	Ten hypothyroid men who discontinued L-T4 therapy and 16 control fertile men	Decrease in seminal volume, progressive forward motility, and the cumulative percentage of mobile forms.
[46]	Observational prospective	Eight men with newly diagnosed primary hypothyroidism	Hypergonadotropism and low serum testosterone were observed during the hypothyroid phase and they restored with thyroxine substitution therapy.
[62]	Prospective observational	Nine men aged 17–35 years and seven men aged 36–46 years with Graves’ disease	Hyperthyroid patients showed greater levels of testosterone, estradiol, LH, and FSH.
[80]	Prospective observational	25 male patients suffering from active Graves’ disease	Hyperthyroidism causes marked alterations of the gonadotropic and PRL axis, asthenospermia, hypospermia, oligospermia, necrospermia, and teratospermia.
[61]	Prospective observational	305 men with idiopathic infertility	Latent thyroid dysfunction had no impact on semen parameters. Elevated TPO-Ab were significantly correlated with pathozoospermia and asthenozoospermia.
[52]	Observational prospective	Twenty-three thyrotoxic male patient	Hyperthyroidism is related to abnormalities in seminal parameters, mainly sperm motility, that improve or normalize when the patients become euthyroid.
[60]	Observational prospective	48 adult men, 34 with hyperthyroidism and 14 with hypothyroidism	Most patients with thyroid hormone disorders experience some sexual dysfunctions, particularly ejaculatory disorders, reversible by normalizing thyroid hormone levels.
[81]	Observational prospective	239 adult men of infertile couples, 39 with normal and 253 with abnormal semen characteristics	The prevalence of thyroid dysfunction and autoimmunity is comparable between men with normal and abnormal semen characteristics.
[82]	Case report	Man with new onset hypothyroidism and slow progressive motility	Three months after starting thyroxine his wife became pregnant
[53]	Observational prospective	Twenty-five hypothyroid men	Hypothyroidism has an adverse effect only on morphology,
[83]	Observational retrospective	298 men with early treated for congenital hypothyroidism	There is no evidence that fecundity is generally lower in young adults treated early for hypothyroidism than in the general population.
[84]	Case report	46 years old infertile man with primary myxedema	Decreased semen volume and severe oligozoospermia; only 2 spermatozoa, elevated levels of serum prolactin and decreased of serum testosterone. After restoration of euthyroidism parameters normalized.
[51]	Prospective cross sectional	66 euthyroid and 24 with hypothyroid men	Hypothyroidism adversely affects erectile function, sperm count, morphology, and motility.
[48]	Observational retrospective	145 euthyroid, 6 with subclinical hyperthyroidism and 12 with subclinical hypothyroidism men of infertile couples	Positive association between fT3 and ejaculate volume, seminal fructose levels, seminal vesicles volume, and testicular echo-texture inhomogeneity. Negative associations between fT4 levels and epididymal body and tail diameter.
[56]	In vitro	Semen samples of 40 euthyroid men with idiopathic infertility incubated with LT4	Addition of T4 to semen samples increased motility
[57]	In vitro	Spermatozoa of 15 euthyroid men with idiopathic infertility incubated with increasing concentrations of LT4	L-T4 significantly reduced sperm necrosis and lipid peroxidation ameliorating chromatin compactness, sperm mitochondrial function, oxidative stress and DNA integrity.
[47]	Observational before-after	40 treatment-naïve patients diagnosed with primary hypothyroidism	Leydig cell function seemed more severely affected by hypothyroidism as compared to Sertoli cell function. Among sperm function parameters, motility was predominantly affected.
[50]	Cross sectional	376 male subjects, among how 160 with abnormal sperm parameters	Disturbance in thyroid hormones are related to alteration of sperm parameters and reproductive hormones.
[85]	Prospective cross sectional	1611 men	TPO-Ab positivity was not associated with infertility.
[59]	Retrospective cross sectional	2282 euthyroid men and 229 with SCH who underwent assisted procreation	SCH was associated with worse clinical outcomes after IVF/ICSI in men ≥35 years old.
[58]	Retrospective cross sectional	4983 euthyroid men and 418 with SCH who underwent IVF/ICSI	SCH was significantly associated with an increased risk of an abnormal DFI.

AITD: autoimmune thyroid disease; L-T4: levothyroxine; fT3: free triiodothyronine; fT4: free thyroxine; TPO-Ab: thyroid peroxidase antibodies; SCH: subclinical hypothyroidism; IVF: in vitro fertilization; ICSI: intracytoplasmic sperm injection; DFI: DNA fragmentation index

Karkun JN, Das RP, Kar AB. Hypothyroidism and reproduction in male rats. Ann Biochem Exp Med. 1962;22:25–30.

 PubMedGoogle Scholar

Howland BE, Ibrahim EA. Hyperthyroidism and gonadotropin secretion in male and female rats. Experientia. 1973;29(11):1398–1399. doi:10.1007/BF01922840.

 PubMedGoogle Scholar

Vilchez-Martinez JA. Study of the pituitary-testicular axis in hypothyroid adult male rats. J Reprod Fertil. 1973;35(1):123–126. doi:10.1530/jrf.0.0350123.

 PubMedGoogle Scholar

Howland BE, Ibrahim EA. Some effects of treatment with triiodothyronine(T3) on reproductive organ weights and gonadotropin levels in the serum and pituitary gland of the male rat. Horm Res. 1974;5(4):193–198. doi:10.1159/000178631.

 PubMedGoogle Scholar

Bruni JF, Marshall S, Dibbet JA, et al. Effects of hyper- and hypothyroidism on serum LH and FSH levels in intact and gonadectomized male and female rats. Endocrinology. 1975;97(3):558–563. doi:10.1210/endo-97-3-558.

 PubMed Web of Science ®Google Scholar

Kalland GA, Vera A, Peterson M, et al. Reproductive hormonal axis of the male rat in experimental hypothyroidism. Endocrinology. 1978;102(2):476–484. doi:10.1210/endo-102-2-476.

 PubMed Web of Science ®Google Scholar

Schneider G, Kopach K, Ohanian H, et al. The hypothalamic-pituitary-gonadal axis during hyperthyroidism in the rat. Endocrinology. 1979;105(3):674–679. doi:10.1210/endo-105-3-674.

 PubMed Web of Science ®Google Scholar

Wong CC, Döhler KD, von Zur Mühlen A. Effects of tri-iodothyronine, thyroxine and isopropyl-di-iodothyronine on thyroid-stimulating hormone in serum and pituitary gland and on pituitary concentrations of prolactin, growth hormone, luteinizing hormone and follicle-stimulating hormone in hypothyroid rats. J Endocrinol. 1980;87(2):255–263. doi:10.1677/joe.0.0870255.

 PubMed Web of Science ®Google Scholar

Chubb C, Nolan C. Animal models of male infertility: mice bearing single-gene mutations that induce infertility. Endocrinology. 1985;117(1):338–346. doi:10.1210/endo-117-1-338.

 PubMed Web of Science ®Google Scholar

Aruldhas MM, Valivullah HM, Govindarajulu P. Specific effect of the thyroid on testicular enzymes involved in carbohydrate metabolism. I. Hypothyroidism. Int J Androl. 1982;5(2):196–204. doi:10.1111/j.1365-2605.1982.tb00248.x.

 PubMedGoogle Scholar

Aruldhas MM, Valivullah HM, Govindarajulu P. Specific effect of thyroid hormone on testicular enzymes involved in carbohydrate metabolism. II. Hyperthyroidism. Biochim Biophys Acta. 1982;715(1):121–125. doi:10.1016/0304-4165(82)90057-5.

 PubMedGoogle Scholar

Chowdhury AR, Gautam AK, Chatterjee BB. Thyroid-testis interrelationship during the development and sexual maturity of the rat. Arch Androl. 1984;13(2–3):233–239. doi:10.3109/01485018408987522.

 PubMed Web of Science ®Google Scholar

Valle LB, Oliveira-Filho RM, Romaldini JH, et al. Pituitary-testicular axis abnormalities in immature male hypothyroid rats. J Steroid Biochem. 1985;23(3):253–257. doi:10.1016/0022-4731(85)90402-9.

 PubMedGoogle Scholar

Matsushima M, Kuroda K, Shirai M, et al. Spermatogenesis in snell dwarf, little and congenitally hypothyroid mice. Int J Androl. 1986;9(2):132–140. doi:10.1111/j.1365-2605.1986.tb00876.x.

 PubMedGoogle Scholar

Chubb C, Henry L. The fertility of hypothyroid male mice. J Reprod Fertil. 1988;83(2):819–823. doi:10.1530/jrf.0.0830819.

 PubMedGoogle Scholar

Weiss SR, Burns JM. The effect of acute treatment with two goitrogens on plasma thyroid hormones, testosterone and testicular morphology in adult male rats. Comp Biochem Physiol A Comp Physiol. 1988;90(3):449–452. doi:10.1016/0300-9629(88)90218-6.

 PubMedGoogle Scholar

Andó S, Panno ML, Beraldi E, et al. Influence of hypothyroidism on in-vitro testicular steroidogenesis in adult rats. Exp Clin Endocrinol. 1990;96(2):149–156. doi:10.1055/s-0029-1211004.

 PubMedGoogle Scholar

Jannini EA, Ulisse S, Piersanti D, et al. Early thyroid hormone treatment in rats increases testis size and germ cell number. Endocrinology. 1993;132(6):2726–2728. doi:10.1210/endo.132.6.8504773.

 PubMed Web of Science ®Google Scholar

Jiang JY, Umezu M, Sato E. Characteristics of infertility and the improvement of fertility by thyroxine treatment in adult male hypothyroid rdw rats. Biol Reprod. 2000;63(6):1637–1641. doi:10.1095/biolreprod63.6.1637.

 PubMed Web of Science ®Google Scholar

Kala N, Ravisankar B, Govindarajulu P, et al. Impact of foetal-onset hypothyroidism on the epididymis of mature rats. Int J Androl. 2002;25(3):139–148. doi:10.1046/j.1365-2605.2002.00338.x.

 PubMedGoogle Scholar

Choudhury S, Chainy GB, Mishro MM. Experimentally induced hypo- and hyper-thyroidism influence on the antioxidant defence system in adult rat testis. Andrologia. 2003;35(3):131–140. doi:10.1046/j.1439-0272.2003.00548.x.

 PubMed Web of Science ®Google Scholar

Umezu M, Kagabu S, Jiang JY, et al. Developmental hormonal profiles in rdw rats with congenital hypothyroidism accompanying increased testicular size and infertility in adulthood. J Reprod Dev. 2004;50(6):675–684. doi:10.1262/jrd.50.675.

 PubMed Web of Science ®Google Scholar

Zamoner A, Barreto KP, Filho DW, et al. Hyperthyroidism in the developing rat testis is associated with oxidative stress and hyperphosphorylated vimentin accumulation. Mol Cell Endocrinol. 2007;267(1-2):116–126. doi:10.1016/j.mce.2007.01.005.

 PubMed Web of Science ®Google Scholar

Chattopadhyay S, Choudhury S, Roy A, et al. T3 fails to restore mitochondrial thiol redox status altered by experimental hypothyroidism in rat testis. Gen Comp Endocrinol. 2010;169(1):39–47. doi:10.1016/j.ygcen.2010.07.014.

 PubMed Web of Science ®Google Scholar

Ibrahim W, Tousson E, Ali EM, et al. Folic acid alleviates oxidative stress and hyperhomocysteinemia involved in testicular dysfunction of hypothyroid rats. Gen Comp Endocrinol. 2011;174(2):143–149. doi:10.1016/j.ygcen.2011.08.012.

 PubMed Web of Science ®Google Scholar

Romano RM, Bargi-Souza P, Brunetto EL, et al. Hypothyroidism in adult male rats alters posttranscriptional mechanisms of luteinizing hormone biosynthesis. Thyroid. 2013;23(4):497–505. doi:10.1089/thy.2011.0514.

 PubMed Web of Science ®Google Scholar

Asker ME, Hassan WA, El-Kashlan AM. Experimentally induced hyperthyroidism influences oxidant and antioxidant status and impairs male gonadal functions in adult rats. Andrologia. 2015;47(6):644–654. doi:10.1111/and.12312.

 PubMed Web of Science ®Google Scholar

El-Kashlan AM, Nooh MM, Hassan WA, et al. Therapeutic potential of date palm pollen for testicular dysfunction induced by thyroid disorders in male rats. PLoS One. 2015;10(10):e0139493. doi:10.1371/journal.pone.0139493.

 PubMed Web of Science ®Google Scholar

Romano RM, Gomes SN, Cardoso NC, et al. New insights for male infertility revealed by alterations in spermatic function and differential testicular expression of thyroid-related genes. Endocrine. 2017;55(2):607–617. doi:10.1007/s12020-016-0952-3.

 PubMed Web of Science ®Google Scholar

Korejo NA, Wei Q, Zheng K, et al. Contemporaneous effects of diabetes mellitus and hypothyroidism on spermatogenesis and immunolocalization of claudin-11 inside the seminiferous tubules of mice. BMC Dev Biol. 2018;18(1):15. doi:10.1186/s12861-018-0174-4.

 PubMedGoogle Scholar

Nascimento Gomes S, do Carmo Corrêa DE, de Oliveira IM, et al. Imbalanced testicular metabolism induced by thyroid disorders: new evidences from quantitative proteome. Endocrine. 2020;67(1):209–223. doi:10.1007/s12020-019-01989-8.

 PubMed Web of Science ®Google Scholar

De La Balze FA, Arrillaga F, Mancini RE, et al. Male hypogonadism in hypothyroidism: a study of six cases. J Clin Endocrinol Metab. 1962;22(2):212–222. doi:10.1210/jcem-22-2-212.

 PubMed Web of Science ®Google Scholar

Griboff SI. Semen analysis in myxedema. Fertil Steril. 1962;13(5):436–443. doi:10.1016/s0015-0282(16)34627-1.

 PubMed Web of Science ®Google Scholar

Clyde HR, Walsh PC, English RW. Elevated plasma testosterone and gonadotropin levels in infertile males with hyperthyroidism. Fertil Steril. 1976;27(6):662–666. doi:10.1016/S0015-0282(16)41896-0.

 PubMed Web of Science ®Google Scholar

Kidd GS, Glass AR, Vigersky RA. The hypothalamic-pituitary-testicular axis in thyrotoxicosis. J Clin Endocrinol Metab. 1979;48(5):798–802. doi:10.1210/jcem-48-5-798.

 PubMed Web of Science ®Google Scholar

Wortsman J, Rosner W, Dufau ML. Abnormal testicular function in men with primary hypothyroidism. Am J Med. 1987;82(2):207–212. doi:10.1016/0002-9343(87)90057-x.

 PubMed Web of Science ®Google Scholar

Röjdmark S, Berg A, Kallner G. Hypothalamic-pituitary-testicular axis in patients with hyperthyroidism. Hormone Res Paediatr. 1988;29(5–6):185–190.

 Google Scholar

Corrales Hernández JJ, Miralles García JM, García Diez LC. Primary hypothyroidism and human spermatogenesis. Arch Androl. 1990;25(1):21–27. doi:10.3109/01485019008987590.

 PubMedGoogle Scholar

Jaya Kumar B, Khurana ML, Ammini AC, et al. Reproductive endocrine functions in men with primary hypothyroidism: effect of thyroxine replacement. Horm Res. 1990;34(5–6):215–218. doi:10.1159/000181828.

 PubMedGoogle Scholar

Hudson RW, Edwards AL. Testicular function in hyperthyroidism. J Androl. 1992;13(2):117–124. doi:10.1002/j.1939-4640.1992.tb01641.x.

 PubMedGoogle Scholar

Abalovich M, Levalle O, Hermes R, et al. Hypothalamic-pituitary-testicular axis and seminal parameters in hyperthyroid males. Thyroid. 1999;9(9):857–863. doi:10.1089/thy.1999.9.857.

 PubMed Web of Science ®Google Scholar

Trummer H, Ramschak-Schwarzer S, Haas J, et al. Thyroid hormones and thyroid antibodies in infertile males. Fertil Steril. 2001;76(2):254–257. doi:10.1016/s0015-0282(01)01875-1.

 PubMed Web of Science ®Google Scholar

Krassas GE, Pontikides N, Deligianni V, et al. A prospective controlled study of the impact of hyperthyroidism on reproductive function in males. J Clin Endocrinol Metab. 2002;87(8):3667–3671. doi:10.1210/jcem.87.8.8714.

 PubMed Web of Science ®Google Scholar

Carani C, Isidori AM, Granata A, et al. Multicenter study on the prevalence of sexual symptoms in male hypo- and hyperthyroid patients. J Clin Endocrinol Metab. 2005;90(12):6472–6479. doi:10.1210/jc.2005-1135.

 PubMed Web of Science ®Google Scholar

Poppe K, Glinoer D, Tournaye H, et al. Is systematic screening for thyroid disorders indicated in subfertile men? Eur J Endocrinol. 2006;154(3):363–366. doi:10.1530/eje.1.02098.

 PubMed Web of Science ®Google Scholar

Burns-Cox C. Sluggish sperms. Lancet. 2007;369(9570):1346. doi:10.1016/S0140-6736(07)60632-1.

 PubMed Web of Science ®Google Scholar

Krassas GE, Papadopoulou F, Tziomalos K, et al. Hypothyroidism has an adverse effect on human spermatogenesis: a prospective, controlled study. Thyroid. 2008;18(12):1255–1259. doi:10.1089/thy.2008.0257.

 PubMed Web of Science ®Google Scholar

Hassani Y, Larroque B, Dos Santos S, et al. Fecundity in young adults treated early for congenital hypothyroidism is related to the initial severity of the disease: a longitudinal population-based cohort study. J Clin Endocrinol Metab. 2012;97(6):1897–1904. doi:10.1210/jc.2011-3286.

 PubMed Web of Science ®Google Scholar

Komiya A, Watanabe A, Kawauchi Y, et al. Severe oligozoospermia in a patient with myxedema coma. Reprod Med Biol. 2012;11(4):207–211. doi:10.1007/s12522-012-0129-6.

 PubMedGoogle Scholar

Nikoobakht MR, Aloosh M, Nikoobakht N, et al. The role of hypothyroidism in male infertility and erectile dysfunction. Urol J. 2012;9(1):405–409.

 PubMed Web of Science ®Google Scholar

Lotti F, Maseroli E, Fralassi N, et al. Is thyroid hormones evaluation of clinical value in the work-up of males of infertile couples? Hum Reprod. 2016;31(3):518–529. doi:10.1093/humrep/dev338.

 PubMed Web of Science ®Google Scholar

Mendeluk GR, Rosales M. Thyroxin is useful to improve sperm motility. Int J Fertil Steril. 2016;10(2):208–214. doi:10.22074/ijfs.2016.4911.

 PubMedGoogle Scholar

Condorelli RA, La Vignera S, Mongioì LM, et al. Thyroid hormones and spermatozoa: in VitroEffects on sperm mitochondria, viability and DNA integrity. J Clin Med. 2019;8(5):756. doi:10.3390/jcm8050756.

 PubMed Web of Science ®Google Scholar

Ambigapathy JS, Kamalanathan S, Sahoo J, et al. Effect of thyroxine replacement on Leydig cell and Sertoli cell function in men with hypothyroidism. Indian J Endocrinol Metab. 2020;24(3):265–269. doi:10.4103/ijem.IJEM_69_20.

 PubMedGoogle Scholar

Rehman R, Zafar A, Fatima SS, et al. Altered sperm parameters and subclinical hypothyroidism; a cross sectional study in Karachi, Pakistan. Int J Clin Pract. 2020;74(9):e13555. doi:10.1111/ijcp.13555.

 PubMed Web of Science ®Google Scholar

Birjandi B, Ramezani Tehrani F, Amouzegar A, et al. The association between subclinical hypothyroidism and TPOAb positivity with infertility in a population-based study: Tehran thyroid study (TTS). BMC Endocr Disord. 2021;21(1):108. 10–1186. doi:10.1186/s12902-021-00773-y.

 Web of Science ®Google Scholar

Rao M, Yang Z, Su C, et al. Paternal subclinical hypothyroidism affects the clinical outcomes of in vitro fertilization/intracytoplasmic sperm injection. Thyroid. 2021;31(1):12–22. doi:10.1089/thy.2020.0154.

 PubMed Web of Science ®Google Scholar

Zhao S, Tang L, Fu J, et al. Subclinical hypothyroidism and sperm DNA fragmentation: a cross-sectional study of 5401 men seeking infertility care. J Clin Endocrinol Metab. 2022;107(10):e4027–e36. doi:10.1210/clinem/dgac458.

 PubMed Web of Science ®Google Scholar