Thyroid gland is the butterfly-shaped organ in the front of the neck. It produces hormones that regulate the body’s metabolism. The relationship between thyroid health and fertility is an important part of conception.

Thyroid Disorders

Thyroid disorders refer to a group of disorders that cause dysregulated functioning of the thyroid gland, resulting in the overproduction (hyperthyroidism) or underproduction (hypothyroidism) of thyroid hormones: triiodothyronine (T3), and thyroxine (T4).

The most common hypothyroid disorder is the autoimmune condition, Hashimoto’s thyroiditis, which is predominant in women.

Graves’ disease, another autoimmune condition, is the most common cause of hyperthyroidism.

How can thyroid disorders effect fertility?

Hypothyroidism and hyperthyroidism can negatively impact fertility—both the ability to become pregnant and the ability to carry a fetus into term. The presence of the thyroid autoimmune antibodies, with or without hyper or hypothyroidism, can also impact fertility.

Fertility is not a female-only concern. Thyroid disorders in men can also affect a couple’s fertility. Dysregulated thyroid function can damage sperm quality and motility, making it difficult for the sperm to enter the egg for fertilization.

Prevalence of hypothyroidism is 2–8% in women in the reproductive age group. Hypothyroidism can affect fertility due to anovulatory cycles, luteal phase defects, hyperprolactinemia, and sex hormone imbalance. (2). Research has shown that abnormal TSH levels can interfere with ovulation. It also can cause the luteal phase (the last half of the cycle after ovulation) disruption by affecting the progesterone levels. If a thyroid disorder is not treated properly, a patient could have difficulty getting pregnant because there can be no ovulation or the progesterone level is not sufficient for the fetus to implant and develope properly. early miscarriage often happend as a result. Therefore, normal thyroid function is necessary for fertility, pregnancy, and to sustain a healthy pregnancy, even in the earliest days after conception. Thyroid evaluation should be done in any woman who wants to get pregnant, with one or more of the following factor:

  • family history of thyroid problem,
  • Irregular menstrual cycle
  • Had miscarriages
  • Unable to conceive after 1 year.
  • Hypothyroidism and Fertility

Too little thyroid hormone can impact fertility in the following ways:

  • Disruption of the menstrual cycle, making it harder to conceive.
  • Interference with the release of an egg from the ovaries (ovulation)
  • Increased risk of miscarriage
  • Increased risk of premature birth
  • The fetus is also prone to placental abnormalities, low birth weight babies, congenital hypothyroidism, abnormal nervous system development and cognitive nervous problems.

Hypothyroidism is more common among women and can often be detected with a simple blood test of thyroid stimulating hormone (TSH). Common symptoms of hypothyroidism include:

  • Frequent and heavy menstrual cycles
  • Fatigue
  • Muscle soreness
  • Forgetfulness
  • Dry skin and hair
  • Weight gain
  • Intolerance to cold

Subclinical hypothyroidism

Still, many women remain undiagnosed, especially women with subclinical hypothyroidism. It is still a controversial topic in the medical community. It is often considered to have Szubklinikus hypothyreosis  if the TSH level is fall between 4-10 mIU/L. The symptoms are not strong, but can be recognized: fatigue, hair loss, weight gain, concentration – memory impairment, depressed state. If not treated properly, Subclinical hypothyroidism can increase the risk of:

  • Menstrual irregularities
  • Coronary heart disease and heart failure.
  • thyroid cancer
  • And it eventually leads to hypothyroidism

The treatment of for subclinical hypothyroid is advised to prevent the cardiovascular risks nd also hypothyroidism which can develop afterward. There are a number of factors which should be consider at the beginning of the treatment, such as the patient’age, other accompanied diseases, a-TPO level, Thyroid globulin level, thyroid ultrasound, etc. The efficacy of treatment for subclinical hypothyroid disorder is also important regard to fertility. If the treatment shows hormon level and symptoms improvements, it is definitely reasonable to continue the treatment for fertility purpose.


The autoimmune condition Graves’ disease is the most common cause of hyperthyroidism. In this case, too much thyroid hormone are produced and they can affect fertility by:

  • Disrupting the menstrual cycle
  • Causing a reduction in sperm count
  • Increasing the risk of miscarriage
  • Increasing the risk for premature birth

If hyperthyroidism is not well controlled, the baby will have growth retardation, hyperthyroidism from the womb, congenital heart disease, premature birth, stillbirth or birth defects.

It is very important for patients to have their thyroid hormones checked and receive appropriate treatment if they wish to have a baby or are already pregnant.

Thyroid autoimmunity and fertility

Autoimmunity can negatively affect fertility, even when TSH levels are within normal range. The immune imbalance caused by thyroid antibodies can impact fertility by:

  • Causing difficulty with fertilization of the egg
  • Causing difficulty with embyo implantation
  • Increasing the risk for miscarriage

If you suffer from autoimmune diseases, it is very important to consult with doctors and have treatment in necessary cases.

Lifestyle interventions

There are a few intervention which can help prevent from thyroid disorders:

  • Do not gain or lose weight suddenly.
  • Avoid stress, especially continuosly stress situation.
  • Maintain adequate sleep.
  • Have a balanced diet with sufficient nutrients. Avoiding fast food, processed food.
  • Do regularly exercise

Please visit your doctor in a regular basis, especially when there are suspicious signs of thyroid disorders.



(2) Prevalence of hypothyroidism in infertile women and evaluation of response of treatment for hypothyroidism on infertility

BOOK AN APPOINTMENT: Dr. Nguyen Hong, Tel: +36 70 943 1878, Email:

Budapest- Vietkimhong Clinic, 1051 Budapest, Arany János street 33, 1.floor.2, doorbell 127. Opening hours: Monday, Wednesday, Friday, 10:00- 17:00