Testing at five to six days. It is possible that instead of removing and testing one or two cells from a two â three day old embryo, some centres may allow the embryo to develop to five - six days, when there are 100-150 cells.
Long-term use of large amounts of vitamin A might cause serious side effects including fatigue, irritability, mental changes, anorexia, stomach discomfort, nausea, vomiting, mild fever, excessive sweating, and many other side effects.
Vitamin A toxicity causes headaches, rashes, coarse hair, hair loss, dry or peeling skin and cracked lips. It also increases the risk of osteoporosis -- thin bones -- and may rarely cause pseudotumor cerebri -- increased pressure in the head characterized by such symptoms as headaches, nausea and vision changes.