Too much or too little vitamin A during development can lead to birth defects

Too much or too little of retinoic acid, a derivative of Vitamin A, can cause babies with birth defects. Retinoic acid is vital in embryonic development, controlling signals between cells to control development of the brain, limbs and many other tissues in embryos. An imbalance is unlikely, however, because the body quickly compensates and degrades excessive retonoic acid or stops degradation when the level is too low.