How do thyroid hormones work?
The thyroid gland produces several hormones, two of which affect ovarian function: thyroxine (T4) and triiodothyronine (T3).
The ovaries have receptors to those hormones. T3 and T4 affect:
- egg growth and maturation
- progesterone and estrogen production by the corpus luteum
- egg fertilization
- embryo viability at its early stages of development
The hormones stimulate the absorption of intestinal cholesterol and the liver’s synthesis of cholesterol used to synthesize sex hormones.
T4 and T3 deficiency in the body may cause a shortage of material necessary to produce female sex hormones, which will disrupt the hormone synthesis and egg maturation processes.
How do malfunctions affect the female reproductive system?
Thyroid gland diseases cause sex gland disruption, which may lead to:
- premature or late sexual development
- ovarian malfunction
- ovarian cyst formation
- lower female sex hormone synthesis
- menstrual cycle disorders and ovulation absence
- increased prolactin production, a cause of infertility
To normalize the reproductive system, it is important to normalize the production of such thyroid hormones as thyroxine (T4), triiodothyronine (T3) and thyroid-stimulating hormone (TSH).
Tests and treatment regimen can be prescribed by the reproductive endocrinologist.
Hypothyroidism symptoms
In up to 34% of cases, hypothyroidism — a thyroid gland disorder when the hormones thyroxine (T4) and triiodothyronine (T3) are not produced in sufficient quantities — is a common cause of female infertility.
The deficiency leads to a disruption in the synthesis, metabolism, and transport of female sex hormones.
This may result in menstrual cycle changes, absence of ovulation, luteal phase deficiency, and an hypothyroidism infertility.
The condition is sometimes accompanied by fatigue, poor concentration and memory problems, muscle and joint pain, weight gain, brittle nails, and skin dryness.
If you are experiencing such low thyroid symptoms, don’t ignore them. It is recommended that you undergo thyroid hormone testing.
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Hyperthyroidism and fertility
One of the causes of conception difficulty (in 4.6% of infertile couples) is hyperthyroidism — an excess in the thyroid hormones thyroxine (T4) and triiodothyronine (T3).
When these hormones circulate in the blood for a long time, it leads to hyperplasia, endometrial polyps, polycystic ovary syndrome (PCOS), uterine bleeding, and absence of menstruation. PCOS can have the following symptoms:
- irritability
- heart palpitations
- weight loss
- hair loss
- fast nail growth
- hand tremors
- heat sensitivity
- skin thinness and smoothness.
If you are sexually active and can’t get pregnant, it would be reasonable to undergo a thyroid examination.
History of updates
Current version (13 November 2021)
Published (30 August 2018)
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