Menstrual disturbances in thyrotoxicosis

Use of levothyroxine for euthyroid, thyroid antibody positive women with infertility: Analyses of aggregate data from a survey of European thyroid specialists (Treatment of Hypothyroidism in Europe by Specialists: An International Survey)

OBJECTIVES

The use of levothyroxine (LT4) treatment aiming to improve fertility in euthyroid women with positive thyroid peroxidase antibodies (TPOAb) is not supported by the available evidence. The aim of the study was to document the use of LT4 by European thyroid specialists in such patients.

DESIGN

The data presented derive from Treatment of Hypothyroidism in Europe by Specialists, an International Survey (THESIS), a questionnaire conducted between 2019 and 2021 to document the management of hypothyroidism by European thyroid specialists. Here, we report the aggregate results on the use of LT4 in infertile, euthyroid women with positive TPOAb.

RESULTS

A total of 2316/5406 (42.8%) respondents stated that LT4 may be indicated in TPOAb positive euthyroid women with infertility. The proportion of those replying positively to this question varied widely across different countries (median 39.4, range 22.9%-83.7%). In multivariate analyses males (OR: 0.8; CI: 0.7-0.9) and respondents >60 years (OR: 0.7; 0.6-0.8) were the least inclined to consider LT4 for this indication. Conversely, respondents managing many thyroid patients ("weekly" [OR: 1.4; CI: 1.0-1.9], "daily" [OR: 1.8; CI: 1.3-2.4]) and practicing in Eastern Europe (OR: 1.5; CI: 1.3-1.9) were most likely to consider LT4.

CONCLUSIONS

A remarkably high number of respondents surveyed between 2019 and 2021, would consider LT4 treatment in TPOAb positive euthyroid women with infertility. This view varied widely across countries and correlated with sex, age and workload, potentially influencing patient management. These results raise concerns about potential risks of overtreatment.

Menstrual Cycle Characteristics in Women With and Without Thyroid Disease

INTRODUCTION

This study was designed to evaluate the frequency and type of menstrual disorders in thyroid dysfunction. The relationship between thyroid dysfunction and menstrual disorders has been known for a long time. The menstrual cycle should be checked in women with thyroid dysfunction. On the contrary, women with menstrual irregularities should be investigated for thyroid dysfunction.

METHODS

Women who presented to our hospital's internal medicine and endocrinology clinics that recently diagnosed thyroid dysfunction were included. The patients were divided into five groups (subclinical hypothyroidism, overt hypothyroidism, subclinical hyperthyroidism, overt hyperthyroidism, and euthyroid) according to thyroid functions. They were questioned regarding the amount, frequency, and duration of menstrual bleeding. The prevalence of menstrual disturbances, including secondary amenorrhea, hypomenorrhea, oligomenorrhea, hypermenorrhea, polymenorrhea, menorrhagia, metrorrhagia, and menometrorrhagia, was examined in 485 patients and 108 healthy controls.

RESULTS

Hypermenorrhea was significantly more common in patients with overt hypothyroidism (33%) than in controls (6%) (p<0.05). The types and frequencies of menstrual disorders in patients with hyperthyroidism and those with normal thyroid function were not significantly different from those in controls.

CONCLUSION

Menstrual abnormalities frequently occur in women with thyroid dysfunction. Therefore, menstrual dysfunction should be considered when treating patients with thyroid abnormalities.

Impact of thyroid disease on fertility and assisted conception

Thyroid autoimmunity (TAI) and/or thyroid dysfunction are prevalent in women of reproductive age and have independently been associated with adverse fertility and pregnancy outcomes, in the case of spontaneous conception or after assisted reproductive technology (ART). Thus, it seems reasonable to screen for thyrotropin (TSH) and thyroid peroxidase autoantibodies (TPO-abs) in infertile women attempting pregnancy. However, even if the relationship between fertility and thyroid dysfunction and/or TAI persists when properly controlled for other variables, it remains challenging to claim causation. Several studies with different designs (cross sectional, case -control, prospective and retrospective cohort studies) have looked at the association between thyroid autoimmunity, thyroid function and fertility. Heterogeneity among study results are related to small numbers of included patients, poor study design, selection of causes of infertility and different assays used to measure TAI, thyroid hormones and TSH reference values. Indeed, there is no consensus regarding the upper limit of normal for TSH to define thyroid dysfunction and the cut-off levels for intervention. Furthermore, data from interventional trials looking at the impact of levothyroxine treatment on fertility outcome in randomised controlled studies are scarce. Despite the recent update of the guidelines by the American Thyroid Association (ATA) for the Diagnosis and Management of Thyroid Disease during Pregnancy and the postpartum, many questions remain unsettled in ART.

Graves' disease could increase polycystic ovary syndrome and comorbidities in Taiwan

Background: To investigate the association between Graves' disease (GD) and polycystic ovary syndrome (PCOS) and its comorbidities.Methods: Logistic regression was performed to determine the association between the two conditions. Cumulative incidence curves were obtained using the Kaplan-Meier method and log-rank test. Hazard ratios were determined using the Cox proportional hazards regression model.Results: We included 5399 patients with GD as the study group and 10,798 patients without GD as the control group. The cumulative incidence curve of PCOS in patients with GD was significantly higher than that in patients without GD (p = .02). The adjusted hazard ratio for PCOS in patients with GD compared with patients without GD was 1.47 (95%CI = 1.09-1.98). The adjusted odds ratio of hyperlipidemia in patients with GD and PCOS was 2.18 (95%CI = 1.14-4.17) higher than that in patients with GD only.Conclusion: Our study demonstrated that women with GD could be at risk of developing PCOS; additionally, a higher incidence of comorbidities, including hyperlipidemia, was noted in women with GD and PCOS.

The impact of thyroid diseases starting from birth on reproductive function

The aim of this review is to provide relevant information regarding the impact of thyroid disease, starting from birth and mainly concerning hyperthyroidism and hypothyroidism, on reproduction. Hyperthyroidism occurs much less commonly in children than hypothyroidism, with Graves' disease (GD) being the most common cause of thyrotoxicosis in children. Children born with neonatal GD have no defects in the reproductive system that could be related to hyperthyroidism. Current treatment options include antithyroid drugs (ATD), surgery, and radioactive iodine (RAI). In males, normal thyroid function seems important, at least in some parameters, for maintenance of semen quality via genomic or non-genomic mechanisms, either by locally acting on Sertoli cells, Leydig cells, or germ cells, or by affecting crosstalk between the HPT axis and the HPG axis. Sexual behavior may also be affected in thyroxic men, although many of these patients may have normal free testosterone levels. In women, menstrual irregularities are the most common reproduction-related symptoms in thyrotoxicosis, while this disorder is also associated with reduced fertility, although most women remain ovulatory. An increase in sex hormone-binding globulin (SHBG) and androgens, thyroid autoimmunity, and an impact on uterine oxidative stress are the main pathophysiological mechanisms which may influence female fertility. Thyroid hormones are responsible for normal growth and development during pre- and postnatal life, congenital hypothyroidism (CH) being the most common cause of neonatal thyroid disorders, affecting about one newborn infant in 3500. The reproductive tract appears to develop normally in cretins. Today, CH-screening programs allow for early identification and treatment, and, as a result, affected children now achieve normal or near-normal development. Hypothyroidism in males is associated with decreased libido or impotence. Although little is currently known about the effects of hypothyroidism on spermatogenesis and fertility, it has been established that sperm morphology and motility are mainly affected. In women of reproductive age, hypothyroidism results in changes in cycle length and amount of bleeding. Moreover, a negative effect on fertility and higher miscarriage rates has also been described.

Incidence of Thyroid Disease in Adolescent Females Presenting with Heavy Menstrual Bleeding

The incidence of thyroid disease in adolescents with heavy menstrual bleeding is unknown. A retrospective cross-sectional study of 427 adolescents presenting with heavy menstrual bleeding found 0.23% (95% CI 0%-0.7%) had thyroid disease, lower than that expected in the general population. Thyroid testing should only be considered when other symptomatology is present.

The Impact of Autoantibodies on IVF Treatment and Outcome: A Systematic Review

The role of autoantibodies in in vitro fertilization (IVF) has been discussed for almost three decades. Nonetheless, studies are still scarce and widely controversial. The aim of this study is to provide a comprehensive systematic review on the possible complications associated to autoantibodies (AA) impeding the chances of a successful IVF cycle. An Embase, PubMed/Medline and Cochrane Central Database search was performed on 1 December 2018, from 2006 until that date. From the 598 articles yielded in the search only 44 relevant articles ultimately fulfilled the inclusion criteria and were qualitatively analyzed. Five subsets of results were identified, namely, thyroid related AA, anti-phospholipid antibodies, anti-nuclear antibodies, AA affecting the reproductive system and AA related to celiac disease. It may be implied that the majority of auto-antibodies exert a statistically significant effect on miscarriage rates, whereas the effects on clinical pregnancy and live birth rates differ according to the type of auto-antibodies. While significant research is performed in the field, the quality of evidence provided is still low. The conduction of well-designed prospective cohort studies is an absolute necessity in order to define the impact of the different types of autoantibodies on IVF outcome.

Thyroid hormones and menstrual cycle function in a longitudinal cohort of premenopausal women

BACKGROUND

Previous studies have reported that hyperthyroid and hypothyroid women experience menstrual irregularities more often compared with euthyroid women, but reasons for this are not well-understood and studies on thyroid hormones among euthyroid women are lacking. In a prospective cohort study of euthyroid women, this study characterised the relationship between thyroid hormone concentrations and prospectively collected menstrual function outcomes.

METHODS

Between 2004-2014, 86 euthyroid premenopausal women not lactating or taking hormonal medications participated in a study measuring menstrual function. Serum thyroid hormones were measured before the menstrual function study began. Women then collected first morning urine voids and completed daily bleeding diaries every day for three cycles. Urinary oestrogen and progesterone metabolites (estrone 3-glucuronide (E₁ 3G) and pregnanediol 3-glucuronide (Pd3G)) and follicle-stimulating hormone were measured and adjusted for creatinine (Cr).

RESULTS

Total thyroxine (T₄ ) concentrations were positively associated with Pd3G and E₁ 3G. Women with higher (vs lower) T₄ had greater luteal phase maximum Pd3G (Pd3G = 11.7 μg/mg Cr for women with high T₄ vs Pd3G = 9.5 and 8.1 μg/mg Cr for women with medium and low T₄ , respectively) and greater follicular phase maximum E₁ 3G (E₁ 3G = 41.7 ng/mg Cr for women with high T₄ vs E₁ 3G = 34.3 and 33.7 ng/mg Cr for women with medium and low T₄ , respectively).

CONCLUSIONS

Circulating thyroid hormone concentrations were associated with subtle differences in menstrual cycle function outcomes, particularly sex steroid hormone levels in healthy women. Results contribute to the understanding of the relationship between thyroid function and the menstrual cycle, and may have implications for fertility and chronic disease.

Higher TSH Levels Within the Normal Range Are Associated With Unexplained Infertility

CONTEXT

Unexplained infertility (UI), defined as the inability to conceive after 12 months of unprotected intercourse with no diagnosed cause, affects 10% to 30% of infertile couples. An improved understanding of the mechanisms underlying UI could lead to less invasive and less costly treatment strategies. Abnormalities in thyroid function and hyperprolactinemia are well-known causes of infertility, but whether thyrotropin (TSH) and prolactin levels within the normal range are associated with UI is unknown.

OBJECTIVE

To compare TSH and prolactin levels in women with UI and women with a normal fertility evaluation except for an azoospermic or severely oligospermic male partner.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study including women evaluated at a large academic health system between 1 January 2000 and 31 December 2012 with normal TSH (levels within the normal range of the assay and ≤5 mIU/L) and normal prolactin levels (≤20 ng/mL) and either UI (n = 187) or no other cause of infertility other than an azoospermic or severely oligospermic partner (n = 52).

MAIN OUTCOME MEASURES

TSH and prolactin.

RESULTS

Women with UI had significantly higher TSH levels than controls [UI: TSH 1.95 mIU/L, interquartile range: (1.54, 2.61); severe male factor: TSH 1.66 mIU/L, interquartile range: (1.25, 2.17); P = 0.003]. This finding remained significant after we controlled for age, body mass index, and smoking status. Nearly twice as many women with UI (26.9%) had a TSH ≥2.5 mIU/L compared with controls (13.5%; P < 0.05). Prolactin levels did not differ between the groups.

CONCLUSIONS

Women with UI have higher TSH levels compared with a control population. More studies are necessary to determine whether treatment of high-normal TSH levels decreases time to conception in couples with UI.

Ovulation, a sign of health

The concept of the ovarian continuum can be understood as a process that occurs during a woman's lifetime and begins during intrauterine life with fertilization. Women start their reproductive years with approximately five hundred thousand follicles containing oocytes, of which only around five hundred will be released during ovulation. Ovulation has been recognized as an event linked with reproduction; however, recent evidence supports the role of ovulation as a sign of health. The use of biomarkers that help women recognize ovulation enables them to identify their health status. This knowledge helps medical healthcare providers in the prevention, diagnosis, and treatment of different pathologies related with endocrine disorders, gynecological abnormalities, autoimmune, genetic, and neoplastic diseases, as well as pregnancy-related issues. The knowledge of the ovarian continuum and the use of biomarkers to recognize ovulation should be considered a powerful tool for women and medical professionals.

Summary

The ovarian continuum is a process that occurs during a woman's lifetime. It begins during intrauterine life with fertilization and ends with menopause. This process can be greatly affected by different conditions such as changes in hormonal levels and illnesses. Therefore, understanding and promoting the knowledge and use of biomarkers of ovulation in women is a key aspect to consider when evaluating their health status. The knowledge and education about the ovarian continuum should be taken into account as a powerful tool for women and medical professionals.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Zebrafish: A Versatile Animal Model for Fertility Research

The utilization of zebrafish in biomedical research is very common in the research world nowadays. Today, it has emerged as a favored vertebrate organism for the research in science of reproduction. There is a significant growth in amount numbers of scientific literature pertaining to research discoveries in reproductive sciences in zebrafish. It has implied the importance of zebrafish in this particular field of research. In essence, the current available literature has covered from the very specific brain region or neurons of zebrafish, which are responsible for reproductive regulation, until the gonadal level of the animal. The discoveries and findings have proven that this small animal is sharing a very close/similar reproductive system with mammals. More interestingly, the behavioral characteristics and along with the establishment of animal courtship behavior categorization in zebrafish have laid an even stronger foundation and firmer reason on the suitability of zebrafish utilization in research of reproductive sciences. In view of the immense importance of this small animal for the development of reproductive sciences, this review aimed at compiling and describing the proximate close similarity of reproductive regulation on zebrafish and human along with factors contributing to the infertility, showing its versatility and its potential usage for fertility research.

Is thyroid hormones evaluation of clinical value in the work-up of males of infertile couples?

STUDY QUESTION

Is thyroid hormones (TH) evaluation of clinical value in the work-up of males of infertile couples?

STUDY ANSWER

Our results suggest that TH evaluation is not mandatory in the work-up of male infertility.

WHAT IS KNOWN ALREADY

A few previous studies performed on a limited series of subjects reported a negative impact of hyper- and hypo-thyroidism on semen volume, sperm concentration, progressive motility and normal morphology. No previous study has systematically evaluated associations between TH variation, semen parameters and ultrasound characteristics of the male genital tract.

STUDY DESIGN, SIZE AND DURATION

Cross-sectional analysis of a consecutive series of 172 subjects seeking medical care for couple infertility from September 2010 to November 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the entire cohort, 163 men (age 38.9 ± 8.0 years) free of genetic abnormalities were studied. All subjects underwent a complete andrological and physical examination, biochemical and hormonal assessment, scrotal and transrectal colour-Doppler ultrasound (CDUS) and semen analysis (including seminal interleukin 8 levels, sIL-8) evaluation within the same day.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the patients studied, 145 (88.9%) showed euthyroidism, 6 (3.7%) subclinical hyper- and 12 (7.4%) subclinical hypo-thyroidism. No subjects showed overt hyper- or hypo-thyroidism. At univariate analysis, no associations among thyroid-stimulating hormone (TSH) or TH levels and sperm parameters were observed. Conversely, we observed positive associations among free triiodothyronine (fT3) and free thyroxine (fT4) levels, ejaculate volume and seminal fructose levels. In a multivariate model, after adjusting for confounders such as age, body mass index, smoking habit, sexual abstinence, calculated free testosterone, prolactin and sIL-8 levels, only the associations found for fT3 levels were confirmed. When CDUS features were investigated, using the same multivariate model, we found positive associations between fT3 levels and seminal vesicles (SV) volume, both before and after ejaculation (adj. r = 0.354 and adj. r = 0.318, both P < 0.0001), as well as with SV emptying (ΔSV volume; adj. r = 0.346, P < 0.0001) and echo-texture inhomogeneity. In addition, after adjusting for confounders, negative associations between fT4 levels and epididymal body and tail diameters were found. No significant associations between TSH or TH levels and CDUS features of other organs of the male genital tract, including testis and prostate, were found. Finally, when the features of subjects with euthyroidism, subclinical hypo- and hyper-thyroidism were compared, no significant differences in seminal or hormonal parameters were found. Conversely, evaluating CDUS parameters, subjects with subclinical hyperthyroidism showed a higher difference between the SV longitudinal diameters measured before and after ejaculation when compared with that of subclinical hypothyroid men, even after adjusting for confounders (P < 0.007). All the other male genital tract CDUS characteristics did not differ among groups.

LIMITATIONS, REASONS FOR CAUTION

First, the number of patients investigated is relatively small and those with (subclinical) thyroid dysfunctions are an even smaller number; hence, it is therefore difficult to draw firm conclusions. Moreover, the present results are derived from patients consulting an Italian Andrology Clinic for couple infertility, and could have different characteristics from the male general population or from those males consulting general practitioners for reasons other than couple infertility. Finally, due to the cross-sectional nature of the study, neither a causality hypothesis nor mechanistic models can be inferred.

WIDER IMPLICATIONS OF THE FINDINGS

Although no associations between TH and sperm parameters were observed, present data support a positive effect of TH on SV size and a permissive role on the ejaculatory machinery, likely through an action on SV and epididymal contractility. This is the first study reporting such evidence. However, in contrast with the view that TH assessment is important for female fertility, our results do not support a systematic evaluation of thyroid function in males of infertile couples. How TH abnormalities impact male fertility needs to be addressed by further studies.

STUDY FUNDING/COMPETING INTERESTS

No funding was received for the study. None of the authors have any conflict of interest to declare.

Management of Graves' disease: an overview and comparison of clinical practice guidelines with actual practice trends

Over the last century, much has been learned about the pathogenesis, manifestations, and management of Graves' disease leading to the establishment of evidence-based clinical practice guidelines. The joint clinical practice guidelines from the American Thyroid Association and the American Association of Clinical Endocrinologists give recommendations on both the diagnosis and treatment of hyperthyroidism. A survey of clinicians performed that same year, however, revealed that current practices diverge from these recently published guidelines in multiple areas. These differences will need to be assessed serially to determine the impact of the guidelines on future clinical practice and perhaps vice versa.

Female reproduction physiology adversely manipulated by thyroid disorders: a review of literature

Proper thyroid function is vital to have a healthy reproduction system. Female sex hormones are altered due to hypothyroidism and hyperthyroidism. Female reproduction system is negatively manipulated by both hyperthyroidism and hypothyroidism and menstrual disorders are the ultimate consequences. Hypomenorrhea, polymenorrhea and oligomenorrhea are the clinical manifestation associated with hyperthyroidism and hypothyroidism, respectively. The female infertility is also adversely affected by thyrotoxicosis and myxedema, the clinical presentation of hyper and hypothyroidism. The simultaneous existence of autoimmunity which is present among some portion of pregnant women may aggravate the clinical manifestation of thyroid disorders in female reproductive physiology. Abortion, premature infants, low birth infant, are among clinical presentation of overt hypothyroidism. Auto antibody against thyroid stimulating hormone receptor and eventual hyperthyroidism considered as risk factors which require extra attention while the thyroid disorder is clinically managed during pregnancy to prevent the fetus from abnormal metabolism. The aim of this review is to elaborate the adverse role of hyperthyroidism and hypothyroidism in female reproduction physiology.

Paracrine interactions of thyroid hormones and thyroid stimulation hormone in the female reproductive tract have an impact on female fertility

Thyroid disease often causes menstrual disturbances and infertility problems. Thyroid hormone (TH) acts through its receptors, transcription factors present in most cell types in the body. Thyroid stimulating hormone (TSH) stimulates TH synthesis in the thyroid gland, but seems to have other functions as well in the female reproductive tract. The receptors of both TH and TSH increase in the receptive endometrium, suggesting that they are important for implantation, possible by influencing inflammatory mediators such as leukemia inhibitory factor. The roles of these receptors in the ovary need further studies. However, it is likely that the thyroid system is important for both follicular and embryo development. The association between thyroid disease and infertility indicate that TH and TSH affect the endometrium and ovary on the paracrine level.

Endocrine disorders & female infertility

Female infertility occurs in about 37% of all infertile couples and ovulatory disorders account for more than half of these. The ovaries are in continuous interaction with the other endocrine organs. The interplay may account for infertility occurring at different levels and may render the diagnosis of infertility a difficult exercise for the involved physician. A hypothalamic cause of female infertility should be considered in an appropriate clinical context, with tests pointing to a hypogonadotropic hypogonadism. It can be functional, physiological or related to organic causes. Hyperprolactinemia has well characterized effects on the normal gonadal function and treatment is well established. Acromegaly and Cushing's disease may impair fertility at different levels, mechanisms involved however remain ill defined. Thyroid disorders, both hyperthyroidism and hypothyroidism, can interact with the ovaries, through a direct effect on ovarian function, but autoimmunity may be involved, as well as alterations of the sex hormone binding protein levels. Primary ovarian disorders, such as the polycystic ovary syndrome and primary ovarian insufficiency are frequent diseases, for which novel treatments are currently being developed and discussed. We will propose an algorithm for the diagnosis and approach of the female patient presenting with infertility on the basis of the available evidence in literature.

A 27-year-old woman diagnosed as polycystic ovary syndrome associated with Graves' disease

Polycystic ovary syndrome (PCOS) and Graves' disease are the common causes of menstrual irregularity leading to infertility in women of child-bearing age. A 21-year-old female patient visited us with complaints of oligomenorrhea and hand tremor. She was diagnosed as having PCOS and hyperthyroid Graves' disease, simultaneously. She had low body weight (BMI: 16.4 kg/m(2)), mild hirsutism, and thyrotoxicosis. The patient was treated with anti-thyroid drug and beta-blocker for about two years, and then recovered to normal thyroid function. Although some studies have suggested a connection between PCOS and autoimmune thyroiditis, no study indicated that PCOS is associated with Graves' disease until now. Here, we describe the first case report of a lean woman with normal insulin sensitivity presenting PCOS and Graves' disease simultaneously.

Thyroid function and human reproductive health

Via its interaction in several pathways, normal thyroid function is important to maintain normal reproduction. In both genders, changes in SHBG and sex steroids are a consistent feature associated with hyper- and hypothyroidism and were already reported many years ago. Male reproduction is adversely affected by both thyrotoxicosis and hypothyroidism. Erectile abnormalities have been reported. Thyrotoxicosis induces abnormalities in sperm motility, whereas hypothyroidism is associated with abnormalities in sperm morphology; the latter normalize when euthyroidism is reached. In females, thyrotoxicosis and hypothyroidism can cause menstrual disturbances. Thyrotoxicosis is associated mainly with hypomenorrhea and polymenorrhea, whereas hypothyroidism is associated mainly with oligomenorrhea. Thyroid dysfunction has also been linked to reduced fertility. Controlled ovarian hyperstimulation leads to important increases in estradiol, which in turn may have an adverse effect on thyroid hormones and TSH. When autoimmune thyroid disease is present, the impact of controlled ovarian hyperstimulation may become more severe, depending on preexisting thyroid abnormalities. Autoimmune thyroid disease is present in 5-20% of unselected pregnant women. Isolated hypothyroxinemia has been described in approximately 2% of pregnancies, without serum TSH elevation and in the absence of thyroid autoantibodies. Overt hypothyroidism has been associated with increased rates of spontaneous abortion, premature delivery and/or low birth weight, fetal distress in labor, and perhaps gestation-induced hypertension and placental abruption. The links between such obstetrical complications and subclinical hypothyroidism are less evident. Thyrotoxicosis during pregnancy is due to Graves' disease and gestational transient thyrotoxicosis. All antithyroid drugs cross the placenta and may potentially affect fetal thyroid function.

Menstrual disturbances in various thyroid diseases

The prevalence of menstrual disturbances, including secondary amenorrhea, hypomenorrhea, oligomenorrhea, hypermenorrhea, polymenorrhea and irregular menstrual cycle were prospectively examined in 586 patients with hyperthyroidism due to Graves' disease, 111 with hypothyroidism, 558 with euthyroid chronic thyroiditis, 202 with painless thyroiditis and 595 with thyroid tumor. In the overall patient group, the prevalence did not different from that in 105 healthy controls. However, patients with severe hyperthyroidism showed a higher prevalence of secondary amenorrhea (2.5%) and hypomenorrhea (3.7%) than those (0.2% and 0.9%, respectively) with mild or moderate hyperthyroidism. Moreover, patients with severe hypothyroidism had a higher prevalence (34.8%) of menstrual disturbances than mild-moderate cases (10.2%). Menstrual disturbances in thyroid dysfunction were less frequent than previously thought.

[Hierarchy for diagnostic and etiological management in menometrorrhagia]

A strategy to establish the diagnosis and the etiology of menorrhagia is necessary for an adaptated therapeutic care. The cross-examination must endeavour to assess bleedings and their clinical impact, and concentrate on specific pathology (such as hemostasis disorders). Clinical examination may eliminate cervical vaginal pathologies and estimate uterine volume. The diagnosis of pregnancy should always be considered and eliminated and that of iron deficiency anemia will be helpful. Explorations of hemostasis balance will be recommended according to clinical and biological features. Hormonal measurement are not contributive, except in diagnosis of SOPK. Endometrium biopsy with the Pipelle will be systematically performed after 40 years of age or in case of risk factors of endometrial cancer. Transvaginal ultrasonography is the first line exam to recommend in case of proved menorrhagia. Hysteroscopy and hysterosonography will be recommended if ultrasonography is not informative enough, or in case of medical treatment failure. MRI is recommended in an second intention (in case of multiple uterine fibroids, or suspected adenomyosis, and if an arterial embolization is required).

Hypothyroidism has an adverse effect on human spermatogenesis: a prospective, controlled study

BACKGROUND

Abnormalities of spermatogenesis are associated with numerous diseases and aging. The objective of this study was to investigate the impact of hypothyroidism on human spermatogenesis and different sperm function tests.

METHODS

Twenty-five hypothyroid men and 15 normal individuals were investigated. Semen analysis, fructose and acid phosphatase measurements, teratozoospermia index (TZI), and acridine orange test were determined before and 6-9 months after the initiation of treatment with levothyroxine.

RESULTS

Morphology is the only sperm parameter that differs significantly between hypothyroid patients and controls (p < 0.0001). After treatment, morphology improved significantly (p < 0.001). Motility was also decreased before treatment in comparison with controls, and improved after treatment. However, the difference was not significant. TZI correlated with free thyroxine.

CONCLUSIONS

Hypothyroidism has an adverse effect on human spermatogenesis. Morphology is the only sperm parameter that is significantly affected. Motility may also be affected, but further studies regarding this are needed. Screening for thyroid dysfunction in males who present with a defect in spermatogenesis is strongly recommended, and if hypothyroidism is noted, the response to thyroid hormone should be evaluated before initiating other treatments.

The Androgen Excess and PCOS Society criteria for the polycystic ovary syndrome: the complete task force report

OBJECTIVE

To review all available data and recommend a definition for polycystic ovary syndrome (PCOS) based on published peer-reviewed data, whether already in use or not, to guide clinical diagnosis and future research.

DESIGN

Literature review and expert consensus.

SETTING

Professional society.

PATIENTS

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A systematic review of the published peer-reviewed medical literature, by querying MEDLINE databases, to identify studies evaluating the epidemiology or phenotypic aspects of PCOS.

RESULT(S)

The Task Force drafted the initial report, following a consensus process via electronic communication, which was then reviewed and critiqued by the Androgen Excess and PCOS (AE-PCOS) Society AE-PCOS Board of Directors. No section was finalized until all members were satisfied with the contents, and minority opinions noted. Statements were not included that were not supported by peer-reviewed evidence.

CONCLUSION(S)

Based on the available data, it is the view of the AE-PCOS Society Task Force that PCOS should be defined by the presence of hyperandrogenism (clinical and/or biochemical), ovarian dysfunction (oligo-anovulation and/or polycystic ovaries), and the exclusion of related disorders. However, a minority considered the possibility that there may be forms of PCOS without overt evidence of hyperandrogenism, but recognized that more data are required before validating this supposition. Finally, the Task Force recognized and fully expects that the definition of this syndrome will evolve over time to incorporate new research findings.

Thyroid disease and female reproduction

The menstrual pattern is influenced by thyroid hormones directly through impact on the ovaries and indirectly through impact on SHBG, PRL and GnRH secretion and coagulation factors. Treating thyroid dysfunction can reverse menstrual abnormalities and thus improve fertility. In infertile women, the prevalence of autoimmune thyroid disease (AITD) is significantly higher compared to parous age-matched women. This is especially the case in women with endometriosis and polycystic ovarian syndrome (PCOS). AITD does not interfere with normal foetal implantation and comparable pregnancy rates have been observed after assisted reproductive technology (ART) in women with and without AITD. During the first trimester, however, pregnant women with AITD carry a significantly increased risk for miscarriage compared to women without AITD, even when euthyroidism was present before pregnancy. It has also been demonstrated that controlled ovarian hyperstimulation (COH) in preparation for ART has a significant impact on thyroid function, particularly in women with AITD. It is therefore advisable to measure thyroid function and detect AITD in infertile women before ART, and to follow-up these parameters after COH and during pregnancy when AITD was initially present. Women with thyroid dysfunction at early gestation stages should be treated with l-thyroxine to avoid pregnancy complications. Whether thyroid hormones should be given prior to or during pregnancy in euthyroid women with AITD remains controversial. To date, there is a lack of well-designed randomized clinical trials to elucidate this controversy.

Infertility and thyroid disorders

PURPOSE OF REVIEW

This review highlights the 'gap' in knowledge regarding the contribution of thyroid dysfunction in reproduction. Thyroid dysfunction, which is quite prevalent in the population affects many organs including the male and female gonads, interferes with human reproductive physiology, reduces the likelihood of pregnancy and adversely affects pregnancy outcome, thus becoming relevant in the algorithm of reproductive dysfunction.

RECENT FINDINGS

Although menstrual irregularities are common, ovulation and conception can still occur in hypothyroidism, where thyroxine treatment restores a normal menstrual pattern and reverses hormonal changes. Subclinical hypothyroidism may be associated with ovulatory dysfunction and adverse pregnancy outcome. Thyroid autoimmunity increases the miscarriage rate, and thyroxine treatment does not seem to protect. Menstrual disturbances, frequent in thyrotoxicosis are restored following treatment. In males, thyrotoxicosis has a significant but reversible effect on sperm motility. Although radioactive Iodine (I) in ablation doses may transiently affect the gonads, it does not decrease fertility or increase genetic malformation rate in the offspring.

SUMMARY

Awareness of the thyroid status in the infertile couple is crucial, because of its significant, frequent and often reversible or preventable effect on infertility. Many aspects of the role of thyroid disorders however in infertility need further research.

Female infertility and the thyroid

Difficulty to conceive or subfertility constitutes a major psychological burden. Assisted reproductive technology changed significantly the outcome of couples faced with subfertility. These techniques consequently increased tremendously our understanding of the mechanisms underlying reproductive failure and opened new perspectives for future interventions, not only to increase cumulative conception rates after ART, but also spontaneous pregnancy rates. Thyroid dysfunction adversely affects fertility. Many studies imply a role for immunology, including thyroid autoimmunity in conception failure. In this review we attempt to update the available information on the adverse effect of thyroid dysfunction and/or thyroid autoimmunity on subfertility and we propose a rationale for testing and potential treatment options.

Thyroid dysfunction and women's reproductive health

Thyroid dysfunction is extremely common in women and has unique consequences related to menstrual cyclicity and reproduction. Even minimal hypothyroidism can increase rates of miscarriage and fetal death and may also have adverse effects on later cognitive development of the offspring. Hyperthyroidism during pregnancy may also have adverse consequences. Accordingly, thyrotropin (TSH) determination is warranted for all women planning pregnancy or those already pregnant. Replacement doses should be carefully monitored throughout pregnancy because the increased renal iodine loss and estrogen-induced rise in thyroxine-binding globulin (TBG) often result in a higher dose requirement. Although thyroid abnormalities are part of the standard differential diagnosis of menstrual disorders, recent studies indicate that these are relatively infrequent causes. Nonetheless, TSH is still required as part of the laboratory evaluation of women with abnormal cycles. The incidence of postpartum thyroiditis is high--6%-8% in various studies. A TSH should be performed in all postpartum patients who are depressed, who complain of unusual fatigue or anxiety or have any of the classical symptoms of hyperthyroidism or hypothyroidism. Practitioners providing health care for women should be alert to thyroid disorders as possible etiological factors in nonspecific symptoms such as fatigue and depression. However, most women with these symptoms are euthyroid; replacement therapy for them is not indicated. The long-standing dogma of thyroidology that replacement with levothyroxine alone is satisfactory for all hypothyroid patients has recently been questioned but results of trials are inconclusive. Nonetheless, satisfactory regimens can be found for the vast majority of patients.

Serum prolactin and TSH in an in vitro fertilization population: is there a link between fertilization and thyroid function?

PURPOSE

Measurements of TSH and prolactin are generally included in the evaluation of female infertility, but their value in women coming to in vitro fertilization (IVF) has been questioned.

METHODS

In this study, we sought to investigate whether prolactin or TSH, measured in 509 specimens collected prior to therapy, predicted outcome in a prospective study of couples undergoing IVF between 1994 and 2001.

RESULTS

TSH was higher in women whose fertility problem was attributed to a male factor, and prolactin was lower if the measurement was taken during menses. TSH and prolactin were positively correlated (p < 0.0001). Neither TSH nor prolactin levels correlated with overall IVF outcome; however, TSH levels were significantly higher among women who produced oocytes that failed to be fertilized and this finding persisted after adjustment for several covariates, including sperm motility. Among women who had a least one oocyte inseminated, the likelihood that they would have fewer than 50% of their eggs fertilized was significantly related to higher TSH levels in a multivariate model.

CONCLUSION

We conclude that TSH may predict poor fertilization in IVF and reflect the importance of thyroid hormones in oocyte physiology.

Preliminary evidence of genetic anticipation in Graves' disease

Despite strong epidemiologic evidence in favor of a genetic component in the etiology of Graves' disease, few hereditary risk factors have been consistently identified. The term genetic anticipation denotes a decrease in the age of onset as disease is passed through generations. In the past 5 years, genetic anticipation has been described in immune-mediated diseases such as rheumatoid arthritis and chronic inflammatory bowel disease, and recently this phenomenon has been linked to unstable expanded trinucleotide repeat sequences in several diseases. If present in Graves' disease, anticipation could provide clues to its genetic etiology. The aim of the present study was to investigate whether genetic anticipation may occur in Graves' disease. Age at diagnosis and age at ascertainment were registered and compared in 33 same-gender parent-offspring pairs with Graves' disease from multiply affected families primarily ascertained for a genetic linkage study. The mean age at diagnosis was 46.6 years (range, 16-77) in the parents and 34.1 years (range, 16-44) in the children. The difference in the mean age at diagnosis between parents and their children was 12.5 years (95% confidence interval 3.0-21.9), p = 0.010. Children were younger than their parents at diagnosis in 25 of 33 pairs (76%). In 7 pairs (21%), the parent was diagnosed after the child according to the calendar years. Essentially similar results were obtained after controlling for gender and smoking habits. In conclusion, our data suggest that patients in the second affected generation seem to acquire their disease at an earlier time in life in familial cases of Graves' disease, indicating that genetic anticipation might occur.

A prospective controlled study of the impact of hyperthyroidism on reproductive function in males

The aim of this prospective controlled study was to ascertain the effect of hyperthyroidism on sperm quality and composition. We studied 23 thyrotoxic male patients, aged 43.8 +/- 2.4 yr (mean +/- SEM), and 15 healthy male controls of approximately the same age (42.2 +/- 2.2 yr). Two semen analyses at intervals of 2-3 wk were obtained before and about 5 months after euthyroidism was achieved either by methimazole alone (14 patients) or (131)I plus methimazole (9 patients). Total fructose, zinc (Zn), and magnesium (Mg) were also measured in seminal plasma in 16 patients, because 7 had semen volume less than 2 ml. In the control group semen analysis was performed only once. Mean (+/-SEM) semen volume was within normal range both in patients (3.3 +/- 0.2 ml) and controls (3.5 +/- 0.4 ml; P = NS). Mean sperm density was lower in patients, although the difference compared with controls did not reach statistical significance (35.7 +/- 5.3 vs. 51.5 +/- 6.1 x 10(6)/ml; P = 0.062). The same was found with sperm morphology (68 +/- 7% vs. 78 +/- 8%; P = NS). Finally, mean motility was lower in thyrotoxic males than in controls (28 +/- 8% vs. 57 +/- 7%; P < 0.01). After treatment, sperm density and motility improved [35.7 +/- 5.3 vs. 43.3 +/- 6.5 x 10(6)/ml (P = NS) and 28 +/- 8% vs. 45 +/- 7% (P < 0.05), respectively], but sperm morphology did not change (68 +/- 7% vs. 70 +/- 6%; P = NS). Mean values for fructose, Zn, and Mg did not differ between controls and patients either before or after achievement of euthyroidism [9.2 +/- 0.7, 3.0 +/- 0.5, and 4.2 +/- 0.7 nmol/liter vs. 8.6 +/- 0.9, 3.0 +/- 0.5, and 4.7 +/- 0.8 nmol/liter (patients before) and 9.1 +/- 0.7, 3.1 +/- 0.6, and 4.5 +/- 0.9 nmol/liter (patients after treatment) for fructose, Zn, and Mg, respectively]. Moreover, according to the treatment given, no statistically significant differences were found before or after treatment. Finally, seminal plasma fructose, Zn, and Mg levels did not correlate with sperm parameters or with pretreatment thyroid hormone levels. In conclusion, the results of our study indicate that male patients with hyperthyroidism have abnormalities in seminal parameters, mainly sperm motility. These abnormalities improve or normalize when the patients become euthyroid. Restoration of sperm parameters was independent of the treatment provided for the hyperthyroid syndrome. Moreover, seminal plasma elements, such as fructose, Zn, and Mg, did not correlate with sperm density, motility, or morphology.

Focus on primary care. Thyroid function and dysfunction in women

All forms of thyroid disease are more common in women. The reason for this gender predilection has not been entirely elucidated but may relate to the closely intertwined relationship between thyroid function and the female reproductive axis. Thyroid dysfunction influences both menstrual function and fertility, likely through changes in sex hormone levels, gonadotropin release, and possibly ovarian function. Similarly, alterations in reproductive physiology can modulate thyroid function. In such settings as pregnancy, when sex hormone levels fluctuate markedly, variations in thyroid function occur frequently. For the clinician, understanding when such alterations require intervention is critical.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the abnormalities of the female reproductive axis associated with both hypo- and hyperthyroidism, to summarize how female sex hormones affect thyroid function, and to explain the effects of pregnancy on thyroid conditions.

Thyroid disease and female reproduction

OBJECTIVE

To review the menstrual function and fertility in thyroid disease, mainly in hyperthyroidism and hypothyroidism. Also to register the consequences of (131)I therapy, which is used widely in the treatment of Graves' disease and thyroid cancer, on subsequent pregnancies and on fertility in these patients.

DESIGN

A MEDLINE computer search was used to identify relevant studies. The type of menstrual disturbances and the status of fertility were recorded from all the studies found. Also, the fertility and genetic hazard of female patients with Graves' disease and thyroid cancer who were treated with (131)I were registered.

RESULT(S)

Both hyperthyroidism and hypothyroidism may result in menstrual disturbances. Menstrual abnormalities are less common now than in previous series. In a recent study, we found that only 21.5% of 214 thyrotoxic patients had some type of menstrual disturbance, compared to 50 to 60% in some older series. The most common manifestations are hypomenorrhea and oligomenorrhea. According to the results of endometrial biopsies, most thyrotoxic women remain ovulatory. Moreover, the genetic hazard incident to radioiodine therapy in Graves' disease and thyroid carcinoma is very small; exposure to (131)I does not cause reduced fecundity, and the risk of loss of fertility is not a contraindication for its use in these patients. mIn hypothyroidism, the frequency of menstrual irregularities has very recently been reported to be 23.4% among 171 hypothyroid patients studied. This is much less than that reported in previous studies, which showed that 50 to 70% of hypothyroid female patients had menstrual abnormalities. The most common manifestation is oligomenorrhea. Severe hypothyroidism is commonly associated with failure of ovulation. Ovulation and conception can occur in mild hypothyroidism. These pregnancies are, however, often associated with abortions, stillbirths, or prematurity. The latter may be of greater clinical importance in infertile women with unexplained infertility.

CONCLUSION(S)

These new data, mainly concerning menstrual abnormalities in hyperthyroidism and hypothyroidism, are inconsistent with what is generally believed and written in the classic thyroid textbooks and indicate that such opinions should be revised.

The hypothalamic-pituitary-thyroid axis and the female reproductive system

Increasing evidence derived from experimental and clinical studies suggests that the hypothalamic-pituitary-thyroid axis (HPT) and the hypothalamic-pituitary-ovarian axis (HPO) are physiologically related and act together as a unified system in a number of pathological conditions. The suggestion that specific thyroid hormone receptors at the ovarian level might regulate reproductive function, as well as the suggested influence of estrogens at the higher levels of the HPT axis, seems to integrate the reciprocal relationship of these two major endocrine axes. Both hyper- and hypothyroidism may result in menstrual disturbances. In hyperthyroidism the most common manifestation is simple oligomenorrhea. Anovulatory cycles are very common. Increased bleeding may also occur, but it is rare. Hypothyroidism in girls can cause alterations in the pubertal process; this is usually a delay, but occasionally it can result in pseudo-precocious puberty. In mature women hypothyroidism usually is associated with abnormal menstrual cycles characterized mainly by polymenorrhea, especially anovulatory cycles, and an increase in fetal wastage.

Disturbances of menstruation in hypothyroidism

OBJECTIVES

Most thyroid textbooks describe hypothyroidism resulting in changes in the length of the menstrual cycle and in the amount of bleeding. Our experience at a busy thyroid clinic had given a picture which differs from that presented in the literature. The aim of this study was to determine the frequency and type of menstrual irregularities in premenopausal hypothyroid patients.

DESIGN AND PATIENTS

We investigated the menstrual history, starting 6 months before the discovery of the disease, in 171 female premenopausal hypothyroid patients and 214 normal controls, with similar age and body mass index (BMI).

MEASUREMENTS

TSH, TT4, TT3 and thyroid antibodies were measured by radioimmunoassay, while BMI was calculated from the ratio of body weight in kg to height in m2.

RESULTS

Of the 171 hypothyroid patients, 131 (76.6%) had regular cycles and 40 (23.4%) irregular periods. Oligomenorrhoea and menorrhagia were the most common features in the latter group. No difference in BMI was found between the patients with or without menstrual abnormalities, or between patients and controls. TSH, TT4 and TT3 levels did not differ between patients with normal and abnormal menstruation. Forty-six (26.9%) out of 171 patients had subclinical hypothyroidism (group A), 42 (24.6%) mild hypothyroidism (group B) and 83 (48.5%) severe hypothyroidism (group C). Thirty-seven from group A (80.4%), 32 from group B (76.2%) and 62 from group C (74.7%) had normal periods. These differences were not statistically significant. Eighty-eight (88.9%) out of 99 patients in whom thyroid antibodies were measured had positive titres. Nineteen (21.6%) of the patients with positive thyroid antibodies had menstrual irregularities. This percentage did not differ from that found in the whole group of patients (23.4%). Out of 214 normal controls, 196 (91.6%) had normal menstruation and 19 (8.4%) irregular cycles. The latter group included mainly women with oligomenorrhoea.

CONCLUSIONS

These data demonstrate that hypothyroidism in women is less frequently associated with menstrual disturbance than was previously described. Also, menstrual irregularities tend to be more frequent in sever hypothyroidism in comparison with mild cases, although this finding was not statistically significant. Oligomenorrhoea and menorrhagia are the most common menstrual disturbances.

Disturbances of menstruation in thyroid disease

Both hyper- and hypothyroidism may result in menstrual disturbances. In hyperthyroidism, amenorrhea was described as early as 1840 by von Basedow. The most common manifestation is simple oligomenorrhea (decreased menstrual flow). Anovulatory cycles are very common. Increased bleeding may occur, but is rare in hyperthyroidism. Nowadays hyperthyroidism is diagnosed earlier than it once was, and so the clinical picture is generally milder. So, menstrual disorders are less common than in previous series. In a recent paper, 21.5% of 214 patients had disturbances in their cycle, compared to 50% in some older series. In hypothyroidism, on the contrary, polymenorrhea (increased menstrual bleeding) is more common. Defects in hemostasis may contribute to this. Anovulation may be represent. Fertility is reduced in both hyper- and hypothyroidism, and the outcome of pregnancy is more often abnormal than in euthyroid women. It is of interest that in juvenile hypothyroidism precocious puberty has been described. This is probably due to a "spillover" effect of the glucoprotein hormones: TSH, which is markedly increased in hypothyroidism, has a small FSH- and LH-like effect. Galactorrhea may also be present in hypothyroidism, possibly because TSH, the hypophyseal TSH-releasing hormone, increases the secretion of both TSH and PRL.