When women of reproductive age are hyperthyroid, it can be difficult to become and stay pregnant. An overactive thyroid (hyperthyroidism) can cause irregular cycles or no ovulation. Once you are pregnant – it increases the risk of miscarriage and other complications.
How do you know if you are hyperthyroid?
The signs can be subtle, so nearly all fertility programmes now do blood tests on all new patients for thyroid disorders at the first visit, regardless of symptoms.
If we suspect hyperthyroidism from the initial test results, we will often order a complete screen.
This means repeating the first test for thyroid-stimulating hormone (TSH) which is what controls how hard your thyroid works. Sometimes, TSH levels can fluctuate dramatically. It’s a good idea to double-check.
We will also test your blood for T4. This hormone is produced by your thyroid and controls your metabolism.
T3 is a second hormone your thyroid produces. It determines how your body uses the energy it produces.
The last of the blood tests we screen for is TRAb (thyroid receptor antibodies). The most common reason for hyperthyroidism in reproductive aged women is elevated levels of thyroid receptor antibodies. This condition is known as Graves disease.
We will likewise do a thyroid ultrasound and a physical exam.
Though it is important (and relatively straightforward) to ensure good thyroid control, it is rare that the thyroid is the only impediment to fertility.
Miscarriage, preterm delivery rates, and pre eclampsia are higher in uncontrolled Graves disease.
Since Graves has been identified before pregnancy, one common treatment option is radioactive iodine. Iodine is picked up by the thyroid, so radioactive iodine will preferentially affect the thyroid…effectively ablating (shrinking) it. As long as we have good control of the thyroid before pregnancy, we do not usually see difficulties for mum or baby.
This may not be “the” answer to your concerns. A Reproductive Endocrinologist is generally not the best person to manage Graves disease. Your RE (or, if pregnant, your Ob/Gyn) will refer you to an Endocrinologist with experience in treating thyroid disorders.