The miracle of life brings joy to many expecting parents when they welcome a new child into the world. But for some couples who try to conceive, they find the going may not be as easy as it is for others. There are a host of diseases or conditions that can impede a woman's ability to get pregnant. One of these is an improperly functioning thyroid gland.
The thyroid gland is a small organ located in the lower front of the neck. It and other glands in the body make up the endocrine system, which creates, stores and releases hormones, our chemical messengers for certain cellular action [source: PubMed Health].
The thyroid makes two important hormones, triiodothyronine (T3) and thyroxine (T4). These hormones regulate a person's metabolism, the body's process of using energy. Metabolism affects practically every function of the human body [source: NEMDIS].
The function of the thyroid can affect a woman's ability to ovulate, thus making it harder to get pregnant. When the thyroid gland either produces too much thyroid hormone (hyperthyroidism) or too little (hypothyroidism), it can interrupt a woman's natural menstrual cycle. This in turn affects her ovulation cycle and can impede her ability to get pregnant [source: Mayo Clinic].
It can be difficult for a woman struggling to get pregnant, especially if she feels frustrated about her situation. But infertility is a serious medical condition, one that impacts around 7.3 million women in the U.S. That's close to 12 percent of women in their child-bearing years [source: ASRM].
But with medical advances, there is a silver lining for women who are having difficulty getting pregnant. In roughly 85 to 90 percent of infertility cases, surgery or medication reverse the condition [source: ASRM]. For women diagnosed with improper thyroid function, medication can be prescribed to help the thyroid gland bring itself into balance.
Let's look at hyperthyroidism and hypothyroidism and their effects on ovulation and pregnancy.
How Hyperthyroidism Affects Ovulation
The more common of the two main thyroid disorders is hyperthyroidism, the over-production of thyroid hormones. This can happen over either a short or long period of time, and it can affect many different functions of the body because of the thyroid's influence over metabolism [source: PubMed Health].
When the thyroid produces too much hormone, it can send the body into a state of over-activity, including high blood pressure, an increased appetite, and intolerance to heat and frequent sweating, as well as other side effects. When it comes to a woman's ovulation cycle, hyperthyroidism can cause irregular or even a complete lack of menstrual cycles [source: PubMed Health].
Most instances of hyperthyroidism are cause by Graves' disease, an autoimmune disorder that directly affects the thyroid. It is often treated by correcting the body's output of thyroid hormones [source: PubMed Health].
It is not impossible for a woman to get pregnant if she shows signs of hyperthyroidism. But, if she does have hyperthyroidism, it has to be treated and monitored by a doctor to protect both her and the baby during pregnancy.
Left unchecked, hyperthyroidism can lead to complications like preeclampsia, a spike in blood pressure late into the pregnancy, as well as premature birth, a low birth weight or even miscarriage [source: NEMDIS]. But these are only symptoms of severe hyperthyroidism. For women who have a mild case of the condition, treatment is not generally needed during pregnancy [source: NEMDIS].
How Low Hypothyroidism Affects Ovulation
Though it is the most common type of thyroid disorder, hyperthyroidism isn't the only problem a woman could have. Her levels could swing the other way in a condition called hypothyroidism.
With hypothyroidism, the thyroid gland doesn't produce enough T3 and T4 hormones, which can affect a person's metabolism in a completely different way than over-production. Some symptoms of the condition include weakness and fatigue, depression, brittle hair or fingernails and unintentional weight gain [source: PubMed Health].
The most common cause of low thyroid production is a condition called Hashimoto's disease, similar to Graves' disease in that it's an autoimmune disorder. With Hashimoto's disease, the body's immune system mistakenly attacks the thyroid itself, damaging the gland's cells and reducing the amount of hormone it can produce [source: NEMDIS].
With cases of hypothyroidism that are less severe, ovulation can occur normally, much like with hyperthyroidism. However, the condition has to be closely monitored and possibly treated if a woman becomes pregnant.
In addition, there is one type of hypothyroidism that is extremely dangerous both to women trying to get pregnant and those already carrying a child. Though rare, a condition known as myxedema coma can occur in women with hypothyroidism.
Myxedema coma is a potentially lethal condition where thyroid hormone levels drop an extreme amount. It is often accompanied by a drop in body temperature, low blood pressure, low blood sugar levels, a decrease in breathing and potential unresponsiveness. Complications from myxedema coma can include infertility, but also miscarriage in a woman already pregnant [source: NEMDIS].
As with any condition, consult your regular medical professional if you have concerns about a potential thyroid problem. The right testing can diagnose thyroid functioning, and your doctor can recommend what treatments are available.
- American Pregnancy Association. "Understanding Ovulation." March 2011. (July 15, 2012) http://www.americanpregnancy.org/gettingpregnant/understandingovulation.html
- American Society for Reproductive Medicine. "Quick Facts About Infertility." 2012. (July 15, 2012) http://www.asrm.org/detail.aspx?id=2322
- American Society for Reproductive Medicine. "Frequently Asked Questions About Infertility." 2012. (July 15, 2012) http://www.reproductivefacts.org/awards/index.aspx?id=3012
- Mayo Clinic. "Infertility: Causes." Sept. 9, 2011. (July 15, 2012) http://www.mayoclinic.com/health/infertility/ds00310/dsection=causes
- National Endocrine and Metabolic Diseases Information Service, National Institutes of Health. "Pregnancy and Thyroid Disease." March 23, 2012. (July 17, 2012) http://www.endocrine.niddk.nih.gov/pubs/pregnancy/
- PubMed Health, U.S. National Library of Medicine. "Graves Disease." April 20, 2010. (July 16, 2012) http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001398/
- PubMed Health, U.S. National Library of Medicine. "Hyperthyroidism." April 19, 2010. (July 16, 2012) http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001396/
- PubMed Health, U.S. National Library of Medicine. "Hypothyroidism." April 19, 2010. (July 16, 2012) http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001393/