Thyroid Disorders, the Menstrual Cycle, and Fertility: What You Need to Know to Protect Your Reproductive Health

Women with thyroid disorders know that the effects of these health problems can be widespread. However, many newly-diagnosed patients are surprised to find out that thyroid dysfunction can interfere with the menstrual cycle, and, by extension, with reproduction and fertility. Conversely, more and more women who report menstrual difficulties and irregularities to their doctors are subsequently being diagnosed with thyroid disorders.

So, what does the little butterfly-shaped gland in your neck have to do with your menstrual cycle? Well, odd as it may initially sound, both are intimately intertwined with the endocrine system, which regulates the creation and distribution of hormones within the body. As a result of this relationship, problems with the menstrual cycle could indicate problems with the thyroid gland -- or vice versa.

Thyroid Disorders and the Menstrual Cycle

Patients with either hyperthyroidism or hypothyroidism may experience menstrual irregularities related to their disorders, although each tends to be associated with a unique pattern of symptoms. This is due to the fact that the variations in the level of thyroid hormone associated with each form of thyroid disease -- either too little or too much -- results in a different outcome in the body.

Women with hypothyroidism produce insufficient levels of thyroid hormones. Menstrual irregularities associated with hypothyroidism include:

• Early onset of menstruation (typically before the age of 10)

• Heavy or prolonged menstruation, also known as menorrhagia

• Irregular menstrual cycles

• Dysmenorrhea, or painful menstruation, including symptoms such as excessive cramps, headache, backache, nausea, aches in the limbs, a bloated sensation, and bowel irregularities

• Amennorhea, or an absence of menstrual periods

On the other hand, women with hyperthyroidism produce too much thyroid hormone and experience problems associated with excessive metabolic rates as a result. They are often faced with a different set of menstruation-related symptoms, including:

• Early or late onset of menstruation, depending on the age at which hyperthyroidism develops

• Unusually light or scant flow during menstrual period

• Sporadic or irregular periods, with long stretches of time between periods

In addition, if women with hyperthyroidism receive excessive doses of pharmaceutical treatment, they may enter into a false hypothyroid state, and begin experiencing the type of menstrual symptoms that are typically associated with hypothyroidism.

Thyroid Disorders and Fertility

Clearly, the extent to which thyroid problems can impact the menstrual cycle has grave implications for a woman’s fertility and ability to carry a pregnancy to term. The menstrual irregularities associated with both hyperthyroidism and hypothyroidism can make ovulation rare and conception difficult, and women with underactive and overactive thyroids have a greater risk of miscarriage, premature birth, and slowed prenatal development.

Often, women suffering from thyroid disorders do not ovulate regularly, if at all. Experts recommend the use of over-the-counter ovulation tests to determine if this might be a problem for you. If it is difficult or impossible for you to pinpoint the time of ovulation, consult with your physician to schedule more detailed medical tests.

In other cases, thyroid disorders can shorten the cycle of fertility. Specifically, the luteal phase of the menstrual cycle can often be truncated in women with thyroid dysfunction. This can make it difficult to determine the optimal time frame for conception, as well as making it more likely that the body will reject an early pregnancy.

Hypothyroidism has been linked with the production of excess amounts of the hormone prolactin, which has been shown to diminish the chances of conception by suppressing ovulation, similar to the way that breastfeeding tends to impede menstruation in the months following childbirth.

What Can You Do?

Although thyroid disorders have been linked to both menstrual irregularities and fertility problems, both of these issues can be addressed with a comprehensive treatment and prevention plan. Here are some guidelines to help you devise a strategy for optimal reproductive health:

• Adhere strictly to your prescribed treatment regimen. In order to minimize menstrual irregularities and stabilize your fertility cycle, it is vital that your thyroid hormone levels remain within the normal range. The single best thing you can do to make this happen is to stick to the treatment plan prescribed by your doctor.

• Keep tabs on your cycle. Recording the start and end date of your period each month can be tedious, but it’s the best way to monitor your regularity and overall reproductive health. In addition to dates and times, also jot down brief notes about the type and amount of flow you observe. That way, if you notice any irregularities, you’ll have all the documentation you need to offer a full description to your doctor.

• When in doubt, consult a specialist. If, after a year or more of following these guidelines, you are still experiencing difficulties with menstrual irregularity or infertility, it may be best to consult with an expert trained in treating reproductive problems in women with endocrine disorders. If fertility is your concern, there may be other health factors that are standing in the way of conception.

For Further Reading

• http://cpmcnet.columbia.edu/dept/thyroid/women.html

• http://www.nlm.nih.gov/medlineplus/ency/article/003149.htm

• http://www.emedicine.com/ped/topic2781.htm