What everyone should know

Transcription

1 The thyroid and infertility: What everyone should know

2 The thyroid and infertility: What everyone should know Having trouble getting pregnant? Your thyroid could be the cause Did you know that undiagnosed thyroid disorders can cause fertility difficulties for both men and women? While infertility can be triggered by many and various factors, suboptimal thyroid function may be that missing link especially when thyroid disease runs in your family. If thyroid problems are the only cause, once treated you should no longer experience infertility. This booklet aims to raise your awareness of the link between the thyroid and infertility. Getting your thyroid checked and finding the right treatment plan if there are problems, is not only beneficial to the health of parents, it is crucial for the health of the baby. Suboptimal thyroid levels are not only a cause of fertility problems, but also of increased risk of miscarriage, premature delivery and other complications, that may impair brain development in a fetus, too. If you have been unsuccessfully trying to get pregnant for longer than the necessary six months to a year, ask your doctor to check the thyroid hormone status of both, men and women. If the thyroid is the cause of your infertility, getting it under control restores fertility and reduces your risk of health complications. Split into helpful sections, this guide contains specific information on thyroid disorders, their impact on fertility, and optimal treatment strategies for couples who are planning for a baby. For quick reference, each section contains a list of frequently asked questions. Additional information is also included. The thyroid and infertility: What everyone should know

3 Your thyroid your fertility Couples may experience infertility problems for many different reasons. For more information visit the website An undiagnosed thyroid problem can certainly be the cause since the hormones produced by the thyroid gland in your neck are in continuous interaction with other, mainly sexual hormones. 1 To preserve a normal function of the testes in men and the ovaries in women the thyroid has to work properly. If not, it produces too much (overactive thyroid) or too little (underactive thyroid) of these hormones which can both adversely affect male and female fertility. Did you know? Over 300 million people worldwide experience problems with their thyroid gland, 2 although over half are presumed to be unaware of their condition. 3 Note Normal thyroid function is important to men and women at all stages of life, but a healthy thyroid is especially key for couples planning for a baby. According to the American Thyroid Association (ATA), thyroid problems can lead to infertility, complications during pregnancy and affect a newborn s neurological development. 4 Thyroid-related fertility problems in men Male infertility is more common than most people suspect, it may surprise you to know that it is involved in thirty percent of couples inability to achieve pregnancy (35 percent is related to female causes, 20 percent to both parties, and in 15 percent no cause can be identified and the spermogram and female work-up are both normal). 5 Male infertility has many causes - from hormonal imbalances, to physical and psychological or behavioral problems. Thyroid hormones, previously thought not to affect male fertility, are now being recognized as having an important role e.g. in sperm production. 6,7 So it is not surprising, that disturbances in your thyroid function could affect your fertility. 8 The good news: Correction of these disorders may restore a man s sexual functions and fertility. is more prevalent in women, an overactive thyroid is an often overlooked or forgotten cause of infertility in men even though it is easy to check and easy to cure. If you are having fertility problems and at the same time one or more symptoms 9 such as nervousness, irritability, fast heart rate, weight loss, increased sensitivity to heat, muscle weakness, increased sweating, trembling hands, hair loss, you should bring up thyroid disease with your doctor, especially if you have a family history of thyroid disease. Problems when things go too fast Hyperthyroidism also known as thyrotoxicosis occurs when the thyroid gland produces and releases excess thyroid hormones into the bloodstream. Although not as common, men can develop hyperthyroidism for a number of reasons, including Graves disease, overmedication with thyroid hormones for treatment of hypothyroidism, too much iodine in the diet, thyroid nodules, or an inflamed thyroid gland (known as thyroiditis). Hyperthyroidism has many different symptoms, although it is unlikely you would develop all of them. In general, the symptoms relate to a speeding up of your body s metabolism. Symptoms in men are essentially the same as they are in women and at first, they may be mistaken for simple nervousness due to stress. Since thyroid disease

4 Problems when things go too slow Thyroid deficiency, medically known as hypothyroidism, is a medical condition which is mainly caused due to inadequate production of the thyroid hormones by the thyroid gland. An underactive thyroid gland slows down your metabolism and is linked to your fertility in several ways. First, reduced libido and erectile dysfunction are common in men with poor thyroid function 11 and these problems can give rise to infertility. Second, hypothyroidism has an adverse effect on sperm morphology 12 (= form and structure of sperm). If you are having fertility problems and one or more symptoms 13 such as fatigue, mental fogginess, poor concentration and memory, depression, increased sensitivity to cold, weight gain, constipation, and dry skin; then you should consult your doctor for thyroid function testing. Do you have an overactive thyroid? Checklist hyperthyroidism yes no Do you have a racing heart? Do you feel nervous or irritable? Do you have prominent, staring eyes? Are you sensitive to warm temperatures? Do you feel weak? Do you sweat a lot? Do your hands tremble? Do you have fast growing fingernails? Do you have frequent bowel movements? Do you lose more hair than usually? Is your skin thin and smooth? Do you lose weight without changing your diet? Do you suffer from erectile dysfunction? Do you have fertility problems? If you answer positively 5 of these questions or more you should see your doctor and tell him/her about your symptoms. There is a possibility that your thyroid is overactive. Note Hyper- and hypothyroid men are more likely to suffer from erectile dysfunction (ED). 6,7 Proper diagnosis and treatment to return a man to normal thyroid function known as euthyroidism was found to reverse most sexual symptoms in men. 10 Therefore, experts recommend thyroid function testing in all men with ED. 10 The thyroid and infertility: What everyone should know

5 Do you have an underactive thyroid? Checklist hypothyroidism yes no Do you have a family history of thyroid diseases? Do you have an autoimmune disease such as type 1 diabetes? Have you had thyroid surgery? Do you feel tired and sleepy most of the time? Do you feel unmotivated, sometimes depressed? Are your concentration and memory poor? Are you sensitive to cold? Did you gain weight or have difficulties losing weight? Do you have problems with digestion? Do you have joint or muscle pain? Are your skin and hair dry? Do you have brittle nails? Are you over 50 years of age? Do you have decreased libido? Do you suffer from erectile dysfunction? Do you have fertility problems? If you answer positively 5 of these questions you should see your doctor and tell him/her about your symptoms. There is a possibility that your thyroid is underactive. Note Iodine deficiency is the most common cause of hypothyroidism worldwide. 14

6 Frequently Asked Questions How common are thyroid problems in men? Although women are five to eight times more likely than men to have thyroid disorders, 4 men can and do develop thyroid problems. It is assumed that up to 50 million men worldwide suffer from thyroid problems. Signs and symptoms in men are essentially the same as they are in women. Since thyroid disease is more prevalent in women, thyroid disorders are an often overlooked cause of infertility in men. 6 What is the link between erectile dysfunction and the thyroid? As challenging as erectile dysfunction is on its own, it can also be a warning sign for more serious problems, such as heart disease or thyroid disorders. 6,7 If you have any thyroid disorder, you are at a much higher risk for erectile dysfunction. 6,7 For example, both hypo- and hyperthyroidism can lead to fatigue and, of course, fatigue can lead to lowered sexual desire and decreased erectile strength. Furthermore, an underactive thyroid can cause low testosterone levels 10 resulting in problems getting and maintaining an erection. If tests show a hormonal imbalance, appropriate treatment of your thyroid problem will restore normal sexual function and thus fertility. 15 Thyroid-related fertility problems in women Thyroid hormones are closely interacting with the female reproductive hormones (estrogens and progesterone) to preserve normal function of the ovaries and maturation of the egg (oocyte). 1 Normal levels of thyroid hormones are thus necessary for normal fertility. Dysfunctions of the thyroid gland with the release of too much (hyperthyroidism) or too little (hypothyroidism) thyroid hormones can alter the balance of reproductive hormones 10 and lead to thyroidrelated fertility problems such as ovulation disorders, irregular periods, and trouble getting pregnant or carrying a baby to term. 16 Even though you may be having a regular menstrual period, you may not be ovulating. Without an egg to be fertilized, conception is a moot point. Sadly, that fact often goes unnoticed for a long time. Since thyroid disease is a common endocrine disorder in women of childbearing age, the first thing to do when you have troubles getting pregnant is to have your thyroid checked, especially if thyroid disease runs in your family. Problems when things go too fast Hyperthyroidism is ten times more common in women than in men 17 and can cause a woman to have difficulties in not only getting pregnant, but also staying pregnant. As you may already know or have read in the chapter on infertility and thyroid disorders in men, hyperthyroidism is a medical condition that causes the thyroid to release excessive amounts of thyroid hormones into the body. The most common reason for hyperthyroidism in reproductive aged women is Graves disease. In this autoimmune disorder the thyroid gland is mistakenly attacked by antibodies. The attack stimulates the gland to overproduce thyroid hormones. Since thyroid hormones are closely interacting with the female reproductive hormones an excess can negatively affect the menstrual cycle. So women, whose thyroids are overactive, tend to have more frequent periods (cycles with intervals of 21 days or fewer) with light bleeding, or even complete absence of their monthly cycles. 10 It should also be noted that you may have a period each month but not be ovulating. The thyroid and infertility: What everyone should know

7 Without the release of an egg, no fertilization can take place, thus no pregnancy. Hyperthyroidism can also cause unhealthy weight loss, another condition that can hamper Note If a thyroid problem is interfering with your menstrual cycle, infertility is reversible. Once the thyroid problem is treated, your cycles should return to normal and you can experience a successful and healthy outcome to your pregnancy desires. your chances of falling pregnant. Most likely you may suffer from weakness, irritability, and fast heart rate among a lot of other symptoms. Individually or in combination, these common symptoms of hyperthyroidism on your general health and your reproductive system may be the cause of menstrual disturbances 10 and thus of your fertility problems. If hyperthyroidism is at the root of your menstrual irregularities, proper treatment with a resulting euthyroidism usually corrects the disturbance. If you are at the right TSH level (TSH: thyroid stimulating hormone, which stimulates your thyroid to produce thyroid hormones) but are still experiencing menstrual problems, you may need to consult with an endocrinologist or gynaecologist who specializes in reproductive disorders. See also Do you have an overactive thyroid? Checklist hyperthyroidism yes no Do you have a racing heart? Do you feel nervous or irritable? Do you have prominent, staring eyes? Are you sensitive to warm temperatures? Do you feel weak? Do you sweat a lot? Do your hands tremble? Do you have fast growing fingernails? Do you have frequent bowel movements? Do you lose more hair than usually? Is your skin thin and smooth? Do you lose weight without changing your diet? Do you have abnormal menstrual periods? Do you have complete absence of the monthly cycle? Do you have problems falling pregnant? If you answer positively 5 of these questions you should see your doctor and tell him/her about your symptoms. There is a possibility that your thyroid is overactive. Note Smoking aggravates the development of menstrual disturbances in women with hyperthyroidism. 18

8 Problems when things go too slow When you have a family history of thyroid disease or any autoimmune disease you have an increased risk for hypothyroidism. 19 If your TSH levels are high and you have symptoms of an underactive thyroid, e.g. weight gain, fatigue, feeling colder than usual, dry skin and hair, and low mood and energy, your fertility may also be affected. Elevated TSH has been observed in 4.6% of cases of female infertility. 20 Women with hypothyroidism could have infrequent and light menstrual bleeding. Some women experience amenorrhea Do you have an underactive thyroid? Checklist hypothyroidism (no menstrual cycles). Other women may have irregular cycles due to problems with ovulation. These menstrual irregularities are approximately three times more common in hypothyroid women than in women with normal thyroid function. 10 With a low-functioning thyroid, levels of prolactin, the hormone that stimulates breast milk production after delivery, may increase and inhibit ovulation. 10 Hypothyroidism is also associated with an increased risk of polycystic ovarian disease (PCOS), a condition that causes cysts on the ovaries and inhibits pregnancy. yes no Do you have a family history of thyroid diseases? Do you have an autoimmune disease such as type 1 diabetes? Have you had thyroid surgery? Do you feel tired and sleepy most of the time? Do you feel unmotivated, sometimes depressed? Are your concentration and memory poor? Are you sensitive to cold? Did you gain weight or have difficulties losing weight? Do you have problems with digestion? Do you have joint or muscle pain? Are your skin and hair dry? Do you have brittle nails? Do you have decreased libido? Do you have abnormal menstrual periods? Do you have complete absence of the monthly cycle? Do you have problems falling pregnant? If you answer positively 5 of these questions, you should see your doctor and tell him/her about your symptoms. There is a possibility that your thyroid is underactive. The most common causes of hypothyroidism are iodine deficiency (see information below) and, where iodine deficiency is uncommon, Hashimoto s disease. This thyroid autoimmune disease (AITD) is the most common autoimmune disorder in women of childbearing age (5 10%) 22 and may result in severe hypothyroidism by gradual destruction of the gland itself. In women with fertility problems AITD is significantly more prevalent than in fertile women. 10 The thyroid and infertility: What everyone should know

9 The good news is that an underactive thyroid can be easily treated with doses of thyroid hormones. If untreated, hypothyroidism often worsens during pregnancy and in addition to affecting the fetus, the condition can lead to long term thyroid problems for the mother later in life. Iodine vital for fertility and conception The World Health Organization has related iodine deficiency to infertility. 23 Lack of iodine in your diet may be to blame for infertility, because this trace mineral is linked to the healthy production of thyroid hormones being vital for fertility and conception. You should take iodine supplements from the point of planning pregnancy through the full duration of pregnancy and breastfeeding. This is not only beneficial for your fertility but also for the health of the baby. Even a mild iodine shortage during pregnancy can have irreversible effects on the baby s early brain and nervous system development with negative impact on mental capacity in later life. 24 Women of childbearing age should have an average iodine intake of 150 micrograms per day. 25 Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider. Frequently Asked Questions How do I know if a thyroid problem is causing me to struggle with fertility? Since many symptoms may be hidden, the best way to know for sure is to ask your doctor for a thyroid check. You should do that, especially, if you have family members with thyroid problems, because thyroid disease often runs in families. How does my thyroid dysfunction relate to infertility? The hormones produced by your thyroid gland are in continuous interaction with other hormones, which normally regulate the function of your ovaries. Hormonal imbalances due to too much (hyperthyroidism) or too little (hypothyroidism) thyroid hormones therefore may interfere with ovulation, thus leading to infertility. 13 Where to get help: Testing and treatment for thyroid-related infertility To start the thyroid test process, you may want to see an endocrinologist. An endocrinologist is a doctor specializing in the diagnosis and treatment of diseases that affect your glands, like the thyroid gland. For optimal treatment of your fertility problems he or she will communicate with your fertility specialist or gynecologist/urologist regarding diagnosis and treatment. availability in the blood (free T3 and T4), it is possible to better understand what type of treatment is required in each individual case. Since thyroid autoimmune disease (AITD) is the most common endocrine disorder in women There are various blood tests conducted for both men and women to test thyroid related infertility causes. In order to diagnose thyroid problems, your doctor will most likely order a thyroid-stimulating hormone (TSH) blood test to check whether your thyroid produces the right amount of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). If your TSH levels are high, your thyroid will not produce enough thyroid hormones (hypothyroidism). If your TSH level is low, than your thyroid produces too much thyroid hormones (hyperthyroidism). Besides TSH blood test, two more tests are also performed to measure the levels of thyroid hormones T4 and T3. By determining the amount (total T3 and T4) of these hormones and their

10 in the reproductive age 10 a test for antibodies may be performed, especially when your thyroid levels are normal, but signs and symptoms of thyroid disorder are present. If you have hypothyroidism, you may need to take thyroid hormone supplements. Treatment of thyroid underfunction with levothyroxine (L-T4), a synthetic thyroxine that works exactly like the thyroid hormone produced by your thyroid gland, 13 usually improves or normalizes menstrual irregularities in women and sperm abnormalities and erectile dysfunction in men, thus restoring fertility. 26 If your hypothyroidism results from too little iodine in your diet, you will be given iodine supplements. If you have hyperthyroidism treatment refers to the specific cause and may include medication, radioactive iodine therapy, or surgery. In women, having radioactive iodine treatment before becoming pregnant usually eliminates the need for antithyroid drugs. For prophylactic reasons a woman should wait at least six months after radioactive iodine treatment before trying to become pregnant. 10 Men who have had radioiodine treatment should wait four months before fathering a child. Note When your thyroid hormone levels are only slightly abnormal (subclinical), your doctor may simply monitor your thyroid function, because there is no consensus on the benefits of treating patients with subclinical thyroid disease. Ask your doctor if he or she will treat your thyroid problem more aggressively to restore your fertility. When it comes to pregnancy, even mild untreated hypothyroidism in the mother is treated with thyroid hormone replacement therapy to prevent an adverse effect on brain development of the baby. 25 Frequently Asked Questions Could it be that I have a thyroid problem even though my blood tests are normal? Absolutely if TSH and FT4 are used as the only indicators of your thyroid health. To make a proper diagnosis and help you a specialist therefore will do additional tests, examine and/or scan your thyroid and look at your individual signs and symptoms. What if I can t get pregnant, but my thyroid tests are normal? Even if the thyroid is able to be controlled it does not always mean you will have all of your infertility barriers lifted. If you have a normal thyroid function or have your thyroid and TSH levels regulated by treatment, and you still don t get pregnant after the requisite six months to a year, you should consult with a fertility specialist for additional treatment and ideas. Is it safe to take thyroid medication while I m trying to become pregnant? Yes, it s safe. In fact, it s unsafe not to take thyroid medication if you need it. The most common reason to take thyroid medicine is to treat hypothyroidism. Levothyroxine, a synthetic form of thyroid hormone, is the usual treatment. It restores normal thyroid hormone levels and thus fertility, when hypothyroidism was the cause of your troubles getting pregnant. Medication with levothyroxine is safe and poses no danger to your developing baby. When my thyroid function is back to normal and I become pregnant - can I stop medication? No. When you stop taking your prescribed drug, hypothyroidism will return. Hypothyroidism during pregnancy can lead to a number of complications. Lack of thyroid hormone affects the brain development and growth of the unborn, and can result in low birth weight, and still birth. You should always consult with a suitably qualified healthcare professional before starting or stopping any treatment. Since with very few exceptions hypothyroidism is a condition that lasts for your whole life, 13 you must continue to take levothyroxine if you re pregnant; and stay in close contact with your doctor. The thyroid and infertility: What everyone should know

11 References 1. Poppe, K, Glinoer D, Tournaye H et al. Thyroid function and assisted reproduction. In: The Thyroid and Reproduction, METS Riga Georg Thieme Verlag Stuttgart 2009; Khan A, Muzaffar M, Khan A et al. Thyroid Disorders, Etiology and Prevalence. J Med Sci. 2002; 2: Canaris GJ, Manowitz NR, Mayor G et al. The Colorado thyroid disease prevalence study. Arch Intern Med. 2000; 160: The American Thyroid Association. General Information Accessed October Healy DL, Trounson AO, Andersen AN. Female infertility: causes and treatment. Lancet 1994; 343: Meikle AW. The interrelationship between thyriod dysfunction and hypogonadism in men and boys. Thyroid 2004; 14 (Suppl 1): S17-S25 7. Krassas GE, Tziomalos K, Papadopoulou F, Pontikides N, Perros P. Erectile dysfunction in patients with hyper- and hypothyroidism: how common and should we treat? J Clin Endocrinol Metab 2008; 93: Singh R, Hamada AJ, Agarwal A. Thyroid hormones in male reproduction and fertility. The Open Reproductive Science Journal 2011; 3: The American Thyroid Association. Hyperthyroidism Brochure Thyroid & Infertility BrochureFV docx Accessed October Krassas GE, Poppe K, Glinoer D. Thyroid function and human reproductive health. Endocr. Rev. 2010; 31: Krassas GE, Perros P. Thyroid disease and male reproductive function. J Endocrinol Invest 2003; 26: Krassas GE, Papadopoulou F, Tziomalos K, Zeginiadou T, Pontikides N. Hypothyroidism has an adverse effect on human spermatogenesis: a prospective, controlled study. Thyroid 2008; 18 (12): The American Thyroid Association. Hypothyroidism Brochure Accessed October The American Thyroid Association. Iodine Deficiency Accessed October 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: Bercovici JP. Menstrual irregularities and thyroid diseases. Feuillets de biologie 2000; 74: Vanderpump MPJ, Tunbridge WMG, French JM et al. The incidence of thyroid disorders in the community: A twenty-year follow-up of the Whickham Survey. Clin Endocrinol 1995; 43: Krassas GE, Pontikides N, Kaltsas T et al. Menstrual disturbances in thyrotoxicosis. Clin Endocrinol (Oxf) 1994; 40: The Hormone Foundation s Patient Guide to the Management of Maternal Hypothyroidism Before, During, and After Pregnancy. De Groot LJ, Stagnaro-Green A, Vigersky R, The Hormone Foundation Accessed October Grassi G, Balsamo A, Ansaldi C et al. Thyroid autoimmunity and infertility. Gynecol Endocrinol 2001; 15: Abalovich M, Gutierrez S et al. Overt and subclinical hypothyroidism complicating pregnancy. Thyroid 2002; 12: Poppe K, Glinoer D. Thyroid autoimmunity and hypothyroidism before and during pregnancy. Human Reproduction Update 2003; 9 (2): WHO. Nutrition publications: Evaluating the public health significance of micronutrient malnutrition Accessed October WHO. Micronutrient deficiencies: Iodine deficiency disorders Accessed October The Endocrine Society (2007) Management of Thyroid Dysfunction during Pregnancy and Postpartum: An Endocrine Society Clinical Practice Guideline Accessed October Krassas, GE. Thyroid disease and female reproduction. Fertil. Steril.2000; 74: Thyroid & Infertility BrochureFV docx

12 Useful resources If you want to know more about thyroid and fertility, visit the following websites: Patient information provided by International Thyroid Awareness Week and sponsored by Merck Serono. Patient information provided by the Endocrine Society of America. Patient information provided by Merck Serono and Merck. Patient information on thyroid health published by the American Thyroid Association (ATA). Patient information by the Thyroid Federation International The information in this Booklet is not intended as a substitute for informed medical advice. You must consult a suitably qualified healthcare professional on any problem or matter which is covered by any information in this booklet before taking any action. This Booklet has been downloaded from the website and was created in November Please refer to the Privacy and Legal Statement on the aforesaid website when reading this. An initiative supported by