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 required and essential for maintenance of normal reproductive function. The recommended daily level during pregnancy is 8,000 IU. Doses of Vitamin A, consumed as retinol of more than 10,000 IU can be harmful to unborn children.n summary, if a woman is taking a multivitamin, prenatal vitamin or Vitamin A supplements containing less than 10,000 IU (as retinol or retinyl), or beta-carotene at any dose, there is no evidence of an increase in the risk of malformations in her baby.