Symptoms of Underactive Thyroid in Women: All You Need to Know
It’s easy to blame continuous exhaustion, unexplained weight gain, hair thinning, and a disturbed menstrual cycle on stress or disturbed sleep. When these symptoms continue for months, they may indicate an underactive thyroid, or hypothyroidism. Because its symptoms develop gradually, the condition can easily go unnoticed and even get worse if left unmanaged.
This guide explains symptoms of underactive thyroid in women, early warning signs, and how a thyroid blood test can help identify thyroid hormone irregularities in females.
What Is the Thyroid Gland and What Does It Do?
The thyroid is a small, butterfly-shaped gland at the front of the neck, just below the voice box. It produces hormones like thyroxine (T4), which the body converts into triiodothyronine (T3). T3 is the active form of thyroid hormone, while T4 serves as its inactive precursor. T3 helps regulate the body’s metabolic functions. These hormones regulate main body functions, such as;
- Heart rate and the strength of heart contractions
- Body temperature and metabolic processes
- Digestion
- Cognitive development
- Muscle and bone health
- Menstrual cycle regulation and reproductive health
- The body’s metabolic rate and energy expenditure
What Is Hypothyroidism?
Hypothyroidism, commonly known as an underactive thyroid disorder, occurs when the thyroid gland does not produce or release enough thyroid hormone into your bloodstream to meet the body’s needs. It can cause fatigue, weight gain, and slow metabolism. One of the common causes of hypothyroidism is Hashimoto’s disease, an autoimmune condition in which the immune system attacks the thyroid gland.
How Common Is Hypothyroidism in the UK?
Hypothyroidism is common among both men and women; however, women are more at risk. In the United Kingdom, it affects around 15 in 1000 women and 1 in 1000 men. Moreover, around 1 in 3500 to 4000 babies are also born with an underactive thyroid, known as congenital hypothyroidism.
Common Signs and Symptoms of Underactive Thyroid in Females
Hypothyroidism can affect several aspects of women’s health, from energy levels and metabolism to skin health and menstrual function. Common symptoms may include:
Note: These symptoms can also occur with other health conditions, and not every woman with hypothyroidism will experience all of them.
Persistent Fatigue and Low Energy
Feeling unusually tired despite getting enough sleep is one of the most common symptoms of an underactive thyroid. Reduced thyroid hormone levels can slow normal body processes, leaving you feeling exhausted and sluggish.
Book Your Energy Test or Chronic Fatigue Test at The National Blood Test Clinic, UK.
Unexplained Weight Gain
Hypothyroidism can cause weight gain by reducing energy expenditure and contributing to fluid retention. The change is often modest, rather than substantial, and weight gain alone does not necessarily indicate a thyroid problem.
Increased Sensitivity to Cold
Women with an underactive thyroid may feel cold when others are comfortable, particularly in their hands and feet. Lower thyroid hormone levels can reduce heat production as the body's metabolism slows.
Dry Skin, Hair Thinning and Brittle Nails
Thyroid hormones help maintain normal skin and hair function. When hormone levels are low, the skin may become dry, rough or scaly, while hair can become brittle or noticeably thinner. Some women also experience increased hair shedding and brittle nails.
Constipation and Slower Digestion
An underactive thyroid can slow down the body's digestive processes, causing food to move more slowly through the digestive tract. This may lead to constipation, bloating and abdominal discomfort. Women with hypothyroidism may experience less frequent bowel movements due to reduced gut motility.
Get Your Blood Test For Fertility Insights
Brain Fog or Forgetfulness
Some women experience brain fog, forgetfulness or difficulty concentrating. Tasks that once felt straightforward may require more effort, and thinking may feel slower than usual. These symptoms can overlap with sleep problems, stress, depression and other health conditions.
Low Mood and Depression
Hypothyroidism may be associated with persistent low mood and depressive symptoms. However, depression has many possible causes, and experiencing low mood alone does not establish that thyroid function is abnormal.
Muscle Soreness and Joint Pain
Low thyroid hormone levels can be associated with muscle aches, cramps, stiffness and weakness. Some women may also experience joint pain or a reduced ability to perform physical activity.
Puffy Face and Hoarse Voice
Fluid retention causing puffiness, particularly around the eyes and face, can be caused by hypothyroidism. Some women also develop a hoarse voice. These changes may be subtle and are more meaningful when they occur alongside other symptoms.
Fertility-Specific Symptoms
Reduced Sex Drive
An underactive thyroid can contribute to a reduced sex drive (low libido) in women. Hypothyroidism can cause fatigue, low energy, mood changes and difficulty concentrating, which may affect sexual desire and interest in intimacy. Hormonal changes associated with thyroid dysfunction may also contribute to reduced libido.
Irregular Menstrual Cycle
Changes in thyroid hormone levels can affect the hormonal processes involved in menstruation. Women with hypothyroidism may experience heavier bleeding, irregular cycles or changes in their usual menstrual pattern. Thyroid dysfunction can also contribute to difficulties with fertility, although many other conditions can affect menstrual health and conception.
Fertility and Pregnancy
An underactive thyroid gland can interfere with normal ovulation process, making conceiving more difficult. Also, healthy development of a baby, especially in early stages of pregnancy, relies on the mother’s thyroid health.
What are the Complications of Untreated Hypothyroidism?
When left untreated, hypothyroidism can lead to several health complications, such as:
- Increased cholesterol levels and a higher risk of heart disease.
- Difficulty conceiving and an increased risk of pregnancy complications, including miscarriage.
- Nerve compression or peripheral neuropathy, which can cause numbness, tingling or pain.
- Goitre or enlargement of the thyroid gland, which can cause swelling in the neck.
- Myxoedema coma - a rare, life-threatening complication of severe, untreated hypothyroidism.
Do The Thyroid and Perimenopause Symptoms Overlap?
Women in their perimenopause stage (40s or 50s) often experience symptoms that overlap with signs of low thyroid. Some of these overlapping symptoms include:
- Weight gain
- Hair thinning
- Skin-related problems
- Lack of focus
- Sleep disturbance
- Mood swings
- Unexplained fatigue and low energy
While some symptoms match, many signs are clearly different for both conditions. Women in their perimenopause experience hot flushes and night sweats, whereas low thyroid levels are usually characterised by cold sensitivity. Similarly, in perimenopause, females often have lighter or skipped periods, whereas underactive thyroid usually causes heavier flow.
Although women can get an idea about their thyroid health by paying attention to their symptoms, proper diagnosis should be made through clinical context and analysis of blood markers through blood tests.
How is an Underactive Thyroid in Women Diagnosed?
An underactive thyroid can be diagnosed through your symptoms, physical examination, and thyroid blood tests, such as thyroid test or complete thyroid profile, when clinically appropriate. Also, your family history of thyroid disease or any other autoimmune condition is considered to make a proper diagnosis.
Your doctor may recommend tests to measure thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels to assess how well your thyroid is functioning.
Explore our Thyroid Panel to check your thyroid hormone levels or our advanced Thyroid Profile for a more comprehensive assessment, including thyroid antibodies.
When Should You See a Doctor?
Book an appointment with your GP if you experience persistent symptoms of an underactive thyroid, particularly if they worsen over time or several occur together. Also seek medical advice if you notice unexplained weight changes, ongoing fatigue, hair thinning or changes in your menstrual cycle. If you are pregnant or planning a pregnancy and suspect a thyroid problem, speak to your doctor promptly, as assessment of thyroid function is important during pregnancy.
Bottom Line
An underactive thyroid can affect energy levels, weight, menstrual and reproductive health, skin, hair and overall wellbeing in women. Recognising these changes and understanding their possible causes can help you take a more informed approach to its treatment. If you have concerns about your thyroid, visit your GP for advice and get your regular blood tests at The National Blood Test Clinic UK to monitor your health.
