Thyroid function tests are blood tests that check the levels of the hormones (chemicals) made by the thyroid gland. Some thyroid function tests also check the level of a hormone made by the pituitary gland in the brain, which acts on the thyroid gland.hyroid function tests are blood tests that check the levels of the hormones (chemicals) made by the thyroid gland. Some thyroid function tests also check the level of a hormone made by the pituitary gland in the brain, which acts on the thyroid gland.
Yes, high intakes of some forms of vitamin A can be harmful. Getting too much preformed vitamin A (usually from supplements or certain medicines) can cause dizziness, nausea, headaches, coma, and even death. High intakes of preformed vitamin A in pregnant women can also cause birth defects in their babies.
Vitamin A is a necessary nutrient during pregnancy that contributes to your health and the development of your baby. However, like many vitamins, vitamin A can be dangerous in high doses.verdose symptoms include headache, nausea, vomiting, drowsiness and blurred vision. According to the American Pregnancy Association, consuming too much vitamin A during the first trimester has been linked to birth defects such as nerve abnormalities.