Hypothyroidism can lead to a number of health problems if it is left untreated; some of the potential complications that may develop are listed here:

Goiter: A large goiter can interfere with swallowing or breathing.

Myxedema coma: A very severe form of hypothyroidism that is seen in people with untreated hypothyroidism. It is generally triggered by infection, illness, exposure to cold or to certain medications. This is a medical emergency and needs immediate treatment.

Clinical signs of Myxedema coma are:

Temperature below normal

Decreased breathing rate and shallow respiration

Low blood pressure

Low blood sugar

Drowsiness, unresponsiveness, unconsciousness

Infertility, miscarriage: Impaired fertility, difficulty in conceiving, easy miscarriage are other complications of hypothyroidism. In addition, infants born to mothers with uncontrolled hypothyroidism have greater risk of being born with birth defects. They are also prone to develop serious intellectual and developmental problems.

Cardiac diseases: Hypothyroidism can lead to increased levels of the ' bad cholesterol' (low-density lipoprotein / LDL). In the long run patients are also at risk for developing an enlarged heart (cardiomyopathy), heart failure and accumulation of fluid around the lungs (pleural effusion).

Psychological problems: Depression, slowing down of the mental faculties, etc. may be seen over a period of time.