How Does the Thyroid Gland Affect Fertility?

April 10 2017 3:35pm

The thyroid gland is shaped like a butterfly, sitting low on the front of your neck. The hormones secreted by the thyroid gland influence factors such as metabolism, growth and body temperature. However, on occasion, the thyroid gland can produce too much or too little thyroid hormone and cause complications for couples hoping to start a family.

Hypothyroidism and Fertility

If a woman has an under-active thyroid condition (hypothyroidism) that is left untreated, her ability to conceive a baby will become hindered. She will likely experience heavier or prolonged periods or even no periods at all. This can cause anaemia. Luckily, the problems with the thyroid that interfere with pregnancy can be treated easily. By taking medication, the thyroid hormone levels will return to normal and the chances of becoming pregnant will drastically improve.

During pregnancy, a woman taking medication for hypothyroidism should take advice from her GP, who may increase the dosage. Depending on circumstances, the GP may also recommend that regular blood tests be carried out throughout the nine months so that the dosage can be altered if required.

Hyperthyroidism and Fertility

On the other hand, an untreated over-active thyroid (hyperthyroidism) will cause lighter, irregular periods and once again, the woman will struggle with conception. Hyperthyroidism is typically caused by Graves’ disease and can result in reduced sperm count in men, another cause of infertility.

If hyperthyroidism is not appropriately regulated when a woman is pregnant, there is an increased risk of miscarriage in the early stages.

During pregnancy, a woman’s body requires enough thyroid hormone to support not only her own increased metabolic needs but also the growing baby’s brain and nervous system. In fact, during the first trimester, the foetus relies solely on the mother’s source of the thyroid hormone, which is received through the placenta. This is why it is so important for the mother to have a normal level of thyroid hormone, both before and during pregnancy, and to seek advice from her GP.


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