The Thyroid And Fertility: What You Need To Know

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One of the most frustrating things for a fertility patient to hear is that they are clinically sub-fertile, but there is nothing wrong with their blood work – in other words, you’re perfectly healthy!  But you’re not getting pregnant and we don’t know why.


At Acubalance, we’re always striving to figure out the “why” – and since thyroid problems are extremely common and difficult to diagnose based on lab results, it’s a topic that often comes up with our fertility patients.  Both men and women can develop thyroid conditions, but it is significantly more common in women.  Often, people suffering from a thyroid condition have very vague symptoms (or no symptoms at all), and lab work from their conventional doctor looks completely normal.  Further investigation with more specific labs and a thorough history and physical exam can reveal that all is not ‘normal’ in thyroid-land.


A healthy functioning thyroid is absolutely essential for optimal fertility.  The thyroid hormones interact closely with the reproductive hormones, and with the ovaries themselves during egg development in women.  When thyroid function is low, ovulation is often delayed and is sometimes prevented, and the eggs will not mature fully.  This can cause symptoms such as ovulatory disorders, recurrent miscarriages, and menstrual irregularities.  Somewhere between 5-20% of women of reproductive age have a thyroid condition; in our practice at Acubalance the percentage is much higher because we typically work with women who are having trouble conceiving.


So a low-functioning thyroid can cause reproductive issues – this is called “hypo-thyroidism”.  Similarly, an over-functioning thyroid (or “hyper-thyroidism”) can wreak havoc on fertility.  Either of these pictures can be inherited or can develop throughout one’s life due to dietary and lifestyle factors, and both can be missed by typical lab work.  There is a third type of condition, however, which is a major cause of an improperly functioning thyroid: it’s called autoimmune thyroid disease, and it means that the immune system is attacking components of the thyroid cascade.  Again, in autoimmune thyroid disease the typical blood work for thyroid function (a lab marker called TSH, Thyroid Stimulating Hormone) is perfectly normal – the antibodies can be present with no effect on the TSH and also no physical symptoms.  It is critically important, then, to test for these antibodies with a full thyroid panel to get a big picture of thyroid function in patients who are having trouble conceiving.


During pregnancy, there is an increased demand for thyroid function along with other changes in a woman’s hormones.  Recurrent miscarriage is common in patients with autoimmune thyroid disease, because the body recognizes that it is not able to keep up with the increased demand for thyroid hormone, and the pregnancy is terminated.  When you think about it, the body’s pretty smart – but with devastating results for couples wishing to have a baby.


Another possible condition that can result from autoimmune thyroid disease is primary ovarian failure – this occurs when antibodies similar to those for the thyroid end up attacking the ovaries.  It is a rare condition, but can be heart breaking for women who develop it.


In men, too, the thyroid is of utmost importance!  Thyroid hormones, in the correct amounts, are required for the development of sperm.  Too much or too little thyroid function can affect this delicate process.  In all men with unexplained poor sperm quality (count, motility or morphology), the thyroid should be screened thoroughly.


Thyroid disease is quickly becoming recognized as a cause of sub-fertility, but it still takes an experienced doctor to know what labs to look at and what range of results is appropriate for healthy fertility.  It is possible to manage an out-of-balance thyroid through diet and lifestyle changes, with acupuncture and Chinese herbs, and with specific nutritional supplements.  At Acubalance, a screen for thyroid function is part of my intake with all patients trying to conceive.  If you have any of the following symptoms, and are trying to conceive, it is important for you to see an experienced doctor who knows how to properly manage the thyroid for fertility.  It can make all the difference!


Symptoms of hypo-thyroidism: fatigue, weakness, constipation, dry skin or hair, feeling cold, irritability or depression, menstrual irregularities, water retention (bloating), muscle cramps, weight gain.  In many cases of hypo-thyroidism, patients have no physical symptoms.


Symptoms of hyper-thyroidism: anxiety, restlessness or irritability, feeling hot, weight loss, hunger, increased sweating, heart palpitations, jitters.  In many cases of hyper-thyroidism, patients have no physical symptoms.


Take care.


In health,



Dr. Kali MacIsaac ND HBSc

Naturopathic Doctor