Thyroid Conditions and Women's Hormonal Health

Thyroid disease is as much as eight times more common in women than men. The thyroid is also a crucial part of your endocrine system, which means that your thyroid's function has a complex and important relationship with your sex hormone function and hormonal balance. As a result, thyroid disease can have an impact on many facets of your hormonal health—from your fertility to pregnancy, breastfeeding to menopause...and more.

Menstrual Issues

Underactive or overactive thyroid conditions—hypothyroidism and hyperthyroidism—are associated with a variety of menstrual irregularities. Hypothyroidism is typically linked to heavier, more frequent periods, while hyperthyroidism is linked to lighter, less frequent periods, or even a complete cessation of periods.

There is also a higher risk of having polycystic ovary syndrome if you have a thyroid condition.

Sex Drive/Libido

Hypothyroidism is frequently linked to a variety of sexual issues in women, including low or nonexistent sex drive (low libido), a lack of interest in sex, slow arousal, an inability to get aroused, and difficulty in achieving orgasm.


  • Anovulatory cycles—menstrual cycles where an egg is not released—are more common in women with hypothyroidism. When an egg is not released, you can't become pregnant.
  • Untreated or undertreated hypothyroidism—especially during the first trimester—is associated with an increased risk of early miscarriage.
  • Elevated thyroid antibodies are associated with an increased risk of infertility, as well as an increased risk of early miscarriage.
  • Untreated or undertreated thyroid disease can also make your assisted reproduction and fertility treatments less successful.

Pregnancy and Postpartum

A period of hormonal change like pregnancy poses a higher risk for the onset or worsening of some thyroid conditions. Pregnancy provides a number of challenges for management of your thyroid disease, so careful planning and oversight are essential to maintain the pregnancy, as well as your health and that of your baby.
A good starting point is to become familiar with the changes you can expect to your thyroid function during pregnancy. One of the most important aspects is your need for sufficient iodine during pregnancy. If you are contemplating pregnancy or are pregnant, you should also be aware of the iodine levels in prenatal vitamins.

A particular challenge is the link between thyroid issues and extreme morning sickness, known as hyperemesis gravidarum.

During the first trimester in particular, pregnancy requires that your thyroid dramatically increase its production of thyroid hormone to meet the needs of your growing baby. When your thyroid cannot respond by producing enough thyroid hormone, the resulting hypothyroidism can pose a risk to the pregnancy and the developing baby.

Hyperthyroidism and Graves' disease in pregnancy pose unique challenges as well, and it's important to be aware of signs, symptoms, the diagnosis process, and proper treatment and monitoring during pregnancy. A thyroid that becomes overactive during pregnancy poses some unique treatment challenges and risks to the pregnancy.

Thyroid nodules and thyroid cancer in pregnancy are not common, but they do require careful evaluation, monitoring, and treatment decisions.

The time after your baby is born—the post-partum period—is another time of hormonal change where thyroid problems can appear or worsen. Thyroid issues are also linked to an increased risk of post-partum depression and breastfeeding difficulties.


Balanced and healthy thyroid function supports healthy breastfeeding, and a thyroid imbalance can interfere with the ability to successfully nurse your baby.

If you are hypothyroid, you may question whether it's safe to take thyroid hormone replacement medication while breastfeeding, but experts do consider it to be safe.

There is, however, some controversy over the safety of breastfeeding while taking antithyroid drugs for hyperthyroidism, so you will want to learn more about the concerns and recommendations of experts.

Also, if your doctor wants to do a radioactive thyroid scan while you're breastfeeding, be aware that you need to follow some very specific guidelines in order to protect your baby.


Perimenopause—the transitional time when hormone levels shift, prior to menstrual periods stopping—is often a time when thyroid conditions can complicate the hormonal picture. This also applies to menopause, which officially starts a year after your last menstrual period.

Perimenopause and menopause can be accompanied by symptoms such as fatigue, mood changes, brain fog, weight gain, and sleep disturbances. These are also symptoms that can point to an undiagnosed or poorly managed thyroid condition. That means that it is especially important for you and your practitioner to explore whether you are experiencing symptoms of perimenopause/menopause, thyroid disease, or both in order to map out an effective treatment approach to resolve your symptoms.

It's also important for you to understand the impact that estrogen—a key hormone included in hormone replacement therapy (HRT)—has on your thyroid.

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Article Sources

  • Braverman, MD, Lewis E., and Robert D. Utiger, MD. Werner and Ingbar's The Thyroid: A Fundamental and Clinical Text. 9th ed., Philadelphia: Lippincott Williams & Wilkins (LWW), 2005.
  • De Groot, Leslie, M.D., Thyroid Disease Manager, Online book. Online
  • Montgomery, Keith, MD. "Sexual Desire Disorders." Psychiatry. 2008 Jun; 5(6): 50–55. PMCID: PMC2695750. Published online 2008 Jun.
  • Oppo, A, Franceschi, et. al. "Effects of hyperthyroidism, hypothyroidism, and thyroid autoimmunity on female sexual function." Journal of Endocrinological Investigation, 2011 Jun;34(6):449-53. doi: 10.3275/7686. Epub 2011 Apr 28.