Hypothyroidism and Fertility
How can the thyroid impact fertility?
What is the thyroid gland?
The thyroid gland is a small butterfly shaped endocrine gland that is located in the lower front of the neck.
It produces thyroid hormones which are carried to and act on every tissue in the body, affecting their function and metabolism.
How can the thyroid impact fertility?
Thyroid autoimmunity (elevated thyroid antibodies) is the most common autoimmune disorder in women of reproductive age. Approximately 10% of women of reproductive age will have thyroid autoimmunity and 2-4% will have overt hypothyroidism (low levels of thyroid hormones).
Thyroid disorders have been associated with ovulation dysfunction, subfertility, implantation failures, and recurrent miscarriage.
I want to get pregnant, what should I do?
Not all women who wish to conceive need to have their thyroid hormones and antibody levels checked.
Thyroid levels should be checked at least 4 weeks before trying to conceive if:
o You have a history of a thyroid problem.
o You are on thyroid medication.
o You have been unable to conceive naturally for more than 6 months.
o You are planning to undergo fertility treatment.
It is recommended you see a specialist if you are planning to undergo fertility treatment or have been found to have abnormal thyroid levels so that the correct blood tests are performed and your treatment can be tailored to your situation.
I am already taking thyroid hormone replacement and am planning fertility what should I do?
See your GP/Specialist and get a thyroid hormone blood test.
Your medication dose may need to be adjusted at least 4 weeks prior to natural conception or a fertility procedure to keep the TSH (Thyroid Stimulating Hormone) within a certain range.
My thyroid levels are normal but I have elevated thyroid antibodies – what does this mean?
Having elevated thyroid antibodies indicates autoimmune dysfunction and an increased risk of developing thyroid problems in the future.
It is still unclear exactly what role elevated antibodies have for fertility and pregnancy in the case of otherwise normal thyroid levels.
If you have elevated antibodies your thyroid hormone levels need to be checked before pregnancy and during as you may require treatment.
There is no good evidence that treatment if you have elevated antibodies but your thyroid hormone levels are normal improves pregnancy rates.
What about male fertility?
Thyroid dysfunction and autoimmunity has been associated with adverse effects on male fertility. It may contribute to reduced sperm quality/quantity, erectile dysfunction and ejaculation problems.
What can you do?
Check thyroid hormone levels only if you have any ejaculation or erectile dysfunction or altered sperm quality or quantity.
As long as the sperm is normal there is no need to delay conception or fertility treatment if the male has thyroid dysfunction.
Written by Dr Veli Kiriakova
Veli is a broadly trained specialist endocrinologist who is passionate about metabolic and preventative health especially weight management. She has a particular interest in all endocrine aspects of women’s health including PCOS, osteoporosis, menopause, diabetes including gestational diabetes and management of thyroid disorders at all life stages including pre-conception and during pregnancy.
Veli strives to empower women to take control of their health by providing expertise, education, empathy and support so they can achieve their goals to become the healthiest version of themselves.