Good thyroid function is an important prerequisite for fertility. Your thyroid gland is just below your Adam’s apple and it sets the pace of your metabolism. Under function (hypothyroidism) and over function (hyperthyroidism) both cause problems with fertility.

Hypothyroidism is quite common so we will address that first. The textbook set of symptoms caused by hypothyroidism is:

  • Feeling cold
  • Gaining weight, or inability to lose weight
  • Hair loss
  • Dry skin
  • Constipation
  • Low mood

You can also experience changes to your menstrual cycle with hypothyroidism: long cycles, heavy bleeding, and prolonged presence of fertile-quality cervical fluid.

When I suspect hypothyroidism, I order a set of four tests: TSH (the hormone that comes from the brain and tells the thyroid gland what to do), T3 (the active form of thyroid hormone), T4 (the inactive form of thyroid hormone) and Anti-TPO (a specific type of immune system attack on the thyroid gland). I use a smaller range of normal for these tests because the tighter range is associated with better rates of pregnancy, lower risk of miscarriage and better pregnancy outcomes.

If you think you might have a hypothyroid problem, you can do a test at home by taking your basal body temperature each morning. Your basal body temperature is your temperature before you get up and start moving around. Your temperature should be 36.1-36.4 degrees Celsius before ovulation and 36.44-37.0 after ovulation. If your temperatures are low, take that information to your naturopathic or medical doctor for further investigation.

Naturopathically, low thyroid function is treated by providing the nutrients important to the thyroid gland and using herbs to stimulate the thyroid gland. It may also be necessary to treat the immune system because immune system attack on the thyroid gland is the most common cause of hypothyroidism. If this treatment does not have enough impact, then supplemental thyroid hormone can be given.

The symptoms that hyperthyroidism produces are almost the opposite of those caused by hypothyroidism:

  • Feeling hot and sweating
  • Anxiety
  • Weight loss and ravenous appetite
  • Tremor
  • Loose bowel movements
  • ‘Velvet’ feel to the skin

Hyperthyoidism causes light bleeding during periods. It can also cause problems for conceiving, increase the risk of miscarriage and cause problems for the postpartum period.

Besides the impact on fertility, thyroid problems have longterm health consequences. For example, hyperthyroidism can cause osteoporosis.

Again, myself and other naturopathic doctors have much more stringent standards for what constitutes good thyroid function. Even if you have had your thyroid tested and been told it was fine, a naturopathic doctor might have a different opinion.

Dr. Andrea Hilborn is a naturopathic doctor in Kingston, Ontario

Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum. The American Thyroid Association Taskforce on Thyroid Disease During Pregnancy and Postpartum, Alex Stagnaro-Green, (Chair),1 Marcos Abalovich,2 Erik Alexander,3 Fereidoun Azizi,4 Jorge Mestman,5 Roberto Negro,6 Angelita Nixon,7 Elizabeth N. Pearce,8 Offie P. Soldin,9 Scott Sullivan,10 and Wilmar Wiersinga11. Thyroid. 2011 Oct; 21(10): 1081–1125. doi:  10.1089/thy.2011.0087