Over 20 per cent women in India live with an undiagnosed thyroid problem and do not even realise that it is the cause of various health issues including infertility, health experts have said.

Thyroid is a small butterfly-shaped gland in the neck that produces thyroid hormones that help regulate the human body's energy use. Sometimes the thyroid makes too much or too little of these hormones. When thyroid hormone production drops (hypothyroidism), the body's processes slow down and change. On the other hand, overactive levels of the hormone (hyperthyroidism) can speed up the body's functions. 

Hypothyroidism or an underactive thyroid could make women unable to conceive. Low levels of thyroid hormone can interfere with ovulation, which impairs fertility, the experts said. "Thyroid is a very common problem especially post 25 years of age and women are four times more prone to thyroid disorders than men," Shobha Gupta, Medical Director and IVF Specialist from Mother's Lap IVF Centre in New Delhi, said in a statement on Thursday.

"Undiagnosed and untreated thyroid disease can be a cause for infertility or frequent miscarriage," she added. Infertility symptoms can include disturbed menstrual cycle, heavy and less frequent periods, low basal body temperature and difficulty in conceiving.

Low thyroid levels, which make the ovaries less able to produce progesterone, also lead to symptoms of premenstrual syndrome (PMS), affecting about 70 per cent of women. An undiagnosed thyroid problem could also be the cause of other health issues including symptoms such as weight gain, fatigue, constipation, muscle and joint aches, sluggishness, intolerance towards cold weather, abnormal and irregular periods and sleeplessness, among others.

"Infertility is a major health threat due to thyroid and many other conditions that are often the direct result of undiagnosed and untreated thyroid conditions," explained Shweta Goswami, Senior Consultant IVF Expert, Jaypee Hospital Noida. 

"In order to lead a healthy life I would recommend that all patients who recognize any of these symptoms should go for a TSH test," Goswami noted. Hyperthyroidism can be treated in many ways such as TSH (thyroid stimulating hormone) test, chest X-ray, T4 or thyroxin test. 

However, a doctor chooses the line of treatment on the basis of a number of variables like the underlying cause of hyperthyroidism, the age of the patient, the size of the thyroid gland and the presence of coexisting medical illnesses. Maintaining a healthy lifestyle, including getting proper diagnosis, weight loss, ample sleep, de-stressing, regular exercise, not ignoring early symptoms and an adequate diet are essential, the experts noted.