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.
During pregnancy, your body needs extra vitamins to support your baby's growth and development. Pregnant women need 600 micrograms (mcg) of folic acid daily to reduce the risk of neural tube defects (problems with the development of the baby's brain and spine). They also need 770 mcg of vitamin A, 2.6 mcg of vitamin B12 and 600 international units (IU) of vitamin D.