If you are trying to conceive and experiencing infertility or recurrent miscarriages, it is important to get your thyroid checked. Thyroid hormones play a large role in fertility and pregnancy and can often be overlooked.
Always check with your physician, as every patient is unique and thyroid levels control important things like how fast your heart beats. But there’s some debate about whether to treat subclinical hypothyroidism (SCH) in women experiencing infertility. SCH is a common, mild thyroid disorder in women of childbearing age and may contribute to increased risk of infertility and early miscarriages.
Hyperthyroidism, Hypothyroidism and Subclinical Hypothyroidism
A simple blood test can determine your thyroid levels. Conventional wisdom suggests that 4.0 should be the upper limit for TSH. However, recent studies have suggested that TSH should be no higher than 2.5 when trying to conceive and 3.0 during pregnancy. Thyroid hormones are synthesized from iodine, so it is important that your iodine levels are optimal. If TSH or iodine levels prove to be too high or too low, this can be easily rectified with medication. Both men and women can have thyroid issues that play a part in fertility.
- Hyperthyroidism: An overactive thyroid produces excess amounts of thyroid hormones. Graves disease and other autoimmune diseases are the most common manifestations. The presence of hyperthyroidism can be measured by performing a TSH blood test. It can cause infrequent periods in women and low sperm counts in men. Once hyperthyroidism is diagnosed it can be treated with medication, radioactive iodine or surgery, after which hormone levels generally return to normal.
- Hypothyroidism: This occurs when the thyroid is underactive and does not produce enough thyroid hormones. Caused by lack of iodine in the diet or by autoimmune diseases such as Hasimoto’s thyroiditis, it is associated with reduced fertility, an increased risk of miscarriage, lower infant intelligence, pre-eclampsia, premature birth and infant death. Plus, low thyroidhormone levels in men can cause poor semen quality, low sperm count, reduced testicular function, erectile dysfunction and a drop in libido. Treatment is usually supplementation with iodine or a synthetic form of thyroid hormone, thyroxine.
- Subclinical hypothyroidism (SCH), also called mild hypothyroidism, is diagnosed when peripheral thyroid hormone levels are within normal reference laboratory range but serum thyroid-stimulating hormone (TSH) levels are mildly elevated. This condition occurs in 3% to 8% of the general population. It is more common in women than men, and its prevalence increases with age. Some studies indicate SCH may be a factor in patients experiencing infertility.
Thyroid antibodies also have an impact on fertility. In some patients, between 8-30% of infertile women, the thyroid is attacked by the immune system as part of an auto-immune disease. The presence of thyroid antibodies increases the risk of pregnancy loss, often at the implantation stage. A blood test will determine if you have this and it can thankfully be treated.
Studies support separate TSH goals for pregnant and non-pregnant adults. Every patient is unique and treatments vary according to procedures – so consult your physician – but for IVF patients we will generally treat if thyroid levels are over 2.5. Again, every patient is unique and treatment plans vary. Treating patients with Subclinical hypothyroidism (SCH) has shown positive outcomes and thyroid medications can be tapered off or adjusted after pregnancy.
Apart from diagnosis and medication, there are lifestyle choices that can help the thyroid function properly like reducing stress. Increasing exercise is also helpful, as it promotes the production of thyroid hormones and increases the sensitivity of the tissues to these hormones. Foods to avoid for thyroid dysfunction include refined grains, sugars, soy products, peanuts and caffeine. Eating a healthy diet, exercising 3x a week, not smoking and lowering alcohol consumption are recommended.