Lesson 2: Initial Testing and Diagnosis
How Your Thyroid Affects Your Fertility

Depending on the results of the TSH blood test, either you will discover that your thyroid is functioning normally, or that it is over or under active. If you get a 'high normal' or a 'low normal' result on the TSH test, you should discuss with your doctor the need for a full thyroid panel (which tests TSH, T3, T4 and thyroid antibodies).

If the thyroid is even slightly dysfunctional, this can cause a host of other problems including irregular periods and miscarriages. The thyroid's release of T4 and T3 controls your body's metabolism, and if the levels are 'off' this can account for a small weight gain or loss.

If your thyroid is not functioning properly, it affects other areas of your endocrine system including reproductive hormones. In order for ovulation to occur each cycle, a woman's hormones must be in balance and be released at the proper times. If the thyroid gland is not in balance and is releasing too little or too much hormone, it disrupts the rest of the endocrine system and can delay or prevent ovulation, cause an increase in prolactin levels, or may contribute to a short luteal phase.

Some women that test normal for TSH, T3 and T4 actually have thyroid antibodies, which can contribute to their fertility problem. The journal Obstetrics & Gynecology has reported that if antithyroid antibodies are present, the risk of miscarriage increases. Research reported in the Journal of Clinical Endocrinology and Metabolism stated that women with antithyroid antibodies have a miscarriage risk twice as high as those women that do not have this antibody.

The best thing that a woman can do is educate herself and to be prepared to show such information to her doctor. If a thyroid disorder is discovered through testing, medications can be prescribed that will help to balance the thyroid and allow it to work properly. Once the thyroid is functioning normally, if the fertility issues were caused by it, the woman's fertility should also return to normal.

If you have been diagnosed with a thyroid condition, you should continue to be tested, as it is possible for your thyroid function to change. It has also been shown that women with a dysfunctional thyroid that want to conceive, their TSH level should be between 1 and 2 for best results.

For additional information on how the thyroid affects fertility, read Mary Shomon's Fertility and Thyroid Disease: Frequently Asked Questions About How to Overcome Thyroid-Related Infertility and Get Pregnant When You Have Thyroid Disease.