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The Impact of Hypothyroidism on the Menstrual Cycle

The Impact of Hypothyroidism on the Menstrual Cycle

Do you have an underactive thyroid (hypothyroidism)? If so, you’re among a lot of company. Over 30% of women over age 35 have a thyroid problem. In fact, women are ten times more likely to experience a thyroid challenge than men! Having a thyroid problem affects virtually every area of your health. The menstrual cycle, and truly all of your body’s processes, depends on proper thyroid health and function.

Hypothyroidism is a common, undetected factor for menstrual cycle problems and fertility issues for many women we work with. For these women, restoring thyroid health can be the answer to solving long-standing menstrual cycle problems, and improving chances for conception and a healthy pregnancy (thyroid problems can increase miscarriage risk).

How Hypothyroidism Affects the Menstrual Cycle

While the link between menstrual cycle problems and thyroid activity is not totally understood, hypothyroidism is known to affect the menstrual cycle in various ways:

  • Thyroid problems go hand in hand with an imbalance between estrogen and progesterone levels, which contributes to menstrual cycle irregularities and many fertility health issues.
  • Low thyroid can increase the risk for adrenal problems and luteal phase defect (shortened luteal phase which can interfere with healthy implantation).
  • An underactive thyroid can increase insulin sensitivity and risk for PCOS, a major cause of anovulation and irregular cycles.
  • Thyroid problems disrupt metabolism and decrease cellular energy, potentially affecting the ability of ovaries to ovulate normally.
  • Hypothyroidism can cause prolactin levels to rise, which may suppress ovulation or decrease chances of conception.

While not all menstrual cycle problems are traced back to hypothyroidism, here are examples of menstrual problems that could be related to a low or under-functioning thyroid gland:

  • Long periods (over 6 days) or short cycles (21 days or less)
  • Heavy periods with flooding (soaking a pad every hour for a number of hours)
  • Painful periods
  • polymenorrhea (frequent periods)
  • early puberty in young girls (before 10 years old)

A Note on Hyperthyroidism and Graves’ disease: Addressing Hyperthyroidism is important to fertility health, too. An overactive thyroid may lead to a short menstrual cycle (less than 5 days), irregular cycles, light cycles or cycles that are far apart. Further, as with hypothyroidism, hyperthyroidism can increase pregnancy risks.

Seek professional support if you have a family history of Graves’ disease or if you suspect you have an overactive thyroid. Symptoms to watch for: menstrual cycle irregularities, unexplained weight loss, bulging eyes or vision changes, rapid heartbeat, anxiety, insomnia, diarrhea, increased sweating and more.

Keep Up With Thyroid Monitoring & Testing

Don’t ignore a potential thyroid problem while working on your fertility. Your body’s metabolism and reproductive function are dependent on it.

If you’re unsure where you stand, here are symptoms of low thyroid to watch for:

unexplained weight gain
cold hands and feet
dry skin, hair and nails

chronically low body temperature
menstrual/period irregularities
muscle weakness and more…

If you have symptoms like this, ask your doctor or reproductive endocrinologist about thyroid testing. Having a full thyroid panel, including Free T3, Free T4, TSH, thyroid antibodies and Reverse T3 can provide a lot of information on your thyroid gland health and function.

If you have a known thyroid challenge, pay attention to how you’re feeling and reach out to your doctor if you need monitoring or a medication adjustment before trying to conceive. For many women, regulating thyroid activity can solve menstrual cycle problems, restore natural fertility and improve chances for a healthy pregnancy.

Learn more about thyroid health, fertility and natural therapies:
Every Woman’s Guide to Hypothyroidism and Fertility
Solve Thyroid Problems Before Conceiving a Baby
Fertility Health: The Link Between the Thyroid and Digestion
Fertility Q&A: Fertility Diet Tips for Thyroid Health


Dr. Christine Traxler M.D., OB/GYN
Dr. Christine Traxler M.D., OB/GYN

Dr. Traxler is a University-trained obstetrician/gynecologist, working with patients in Minnesota for over 20 years. She is a professional medical writer; having authored multiple books on pregnancy and childbirth; textbooks and coursework for medical students and other healthcare providers; and has written over 1000 articles on medical, health, and wellness topics.  Dr. Traxler attended the University of Minnesota College of Biological Sciences and University of Minnesota Medical School,  earning a degree in biochemistry with summa cum laude honors in 1981,  and receiving her Medical Doctorate degree (MD) in 1986.

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