25th May is the World Thyroid Day. Thyroid disorders are one of the most common disorders of hormones in our body. Thyroid is a small gland situated in front of the neck and secretes hormones like thyroxine (T4) and tri-iodo-thyronine (T3). These hormones control various functions of our body like heart, blood pressure, digestion, metabolism, growth, blood formation, brain function etc. But one of the most important function is its association with reproduction.

In both sexes, T3 and T4 are needed for sexual development during puberty so that full maturation from a child to adult occurs. That means development of hair (pubic and axillary hair), beard and moustache in boys, breast in girls, genital organ development in both sexes and menstrual function are dependent on thyroid gland. Finally production of eggs (rather maturation and release) and sperms are also related to it. In adults, thyroid function is needed to maintain the functions of sex glands particularly ovaries and testes. Desire for sex (libido) and performance of sex are also related to thyroid function. 

The thyroid glands in turn is regulated by a hormone secreted from pituitary gland, located inside the brain. That hormone- TSH (thyroid stimulating hormone) controls secretion of T3 and T4., Thyroid gland may be affected by various diseases like autoimmune diseases (body itself destroys its organs), deficiency of iodine, radiation, tumour, congenital causes (cause present from birth) and certain drugs. The result is that thyroid hormone secretion may be reduced (hypothyroidism) or increased (hyperthyroidism). As a result, blood tests for TSH, T3 and T4 are commonly done to detect abnormalities of thyroid gland. If abnormalities are detected, further tests may be advised, e.g., ultrasound and scanning of thyroid gland. 

So what can happen to reproduction if thyroid function is affected? Thyroid disorders are particularly common in females. Menstrual cycle may be irregular (coming every 2 or 3 months) or may be scanty in amount or more commonly very excessive flow. These respond well to correction of thyroid hormone levels by drugs. 

Thyroid disorder is a common cause of anovlation- That is women cannot release eggs in each month. The result is irregular menstruation and infertility- the inability to conceive a child. Often correction of thyroid hormone levels result in pregnancy. 

Please remember if you are trying for pregnancy, then your TSH value should not be the same like other people. We usually treat such women, if TSH is more than 2.5 (this may be normal for labaoratory standards for other people but not for those who plan for preganancy and who are pregnant). 

It can cause low libido, vaginal dryness, reduced orgasm and painful intercourse.

In case of male, the thyroid disease is not very common but is not rare. It can affect sperm production leading to infertility. Apart from that it can affect sexual performance leading to low libido, easy fatigue and erectile dysfunction (ED). All these resolve after proper treatment.

Never ignore checking thyroid status for adolescent boys and girls. It may be responsible for delayed puberty (delay in appearance of male like features in boys and female like features in girls) or precocious puberty (early onset of menstruation or breast development in girls; or early development of beard and moustache in boys). These may be associated with serious disorders and need proper attention.

Pregnancy is a condition where there is tremendous pressure on thyroid gland and it is needed to help in proper development of baby inside uterus. Women with thyroid disorders can have miscarriage, premature delivery, death of baby inside uterus or poor growth of the baby. She can experience bleeding in pregnancy, high blood pressure (preeclampsia) and even heart failure. In initial periods babies depend on mother's thyroid gland for its development. If baby does not get proper amount of thyroid hormones, its brain and body development can be hampered. The brain development can be affected leading to birth of a disabled baby, as it may not be corrected even after treatment. So proper diagnosis and treatment of thyroid diseases in pregnancy are essential. After birth, baby should be tested for thyroid disease and appropriate treatment should be started without any delay.

So, if you feel any of the above problems, please do not hesitate to consult your doctor and request testing of thyroid functions. If drug treatment is started, do not stop the drug without consulting doctor. Uncontrolled thyroid disease can lead to heart attack, stroke and emergency situations like thyrotoxicosis or myxoedema- which can be potentially life threatening if not treated in time.