Typically veins are generally wider than arteries, and therefore the pressure is lower. Capillaries are tiny vessels, so repsent high resistance to the incoming blood, so the rate of blood flow through will be quite low. All blood from the artery eventually passes through capillaries and into the vein.
Other causes of an overactive thyroid can include inflammation of the thyroid due to viruses or bacterial infections. Also, postpartum hyperthyroidism affects women immediately after pregnancy. This is one of the most common postpartum health disorders, and it affects between ten and twenty percent of women.
Worldwide, a lack of dietary iodine is a common cause of an underactive thyroid, because the body needs iodine to make thyroxine. However, iodine deficiency is uncommon in the UK. Babies are sometimes born with an underactive thyroid because the thyroid gland doesn't develop properly in the womb.his damages the thyroid, which means it's not able to make enough of the hormone thyroxine, leading to the symptoms of an underactive thyroid. A condition called Hashimoto's disease is the most common type of autoimmune reaction that causes an underactive thyroid.