R.H.
it's ok to color or just highlight anytime, from what my doct's say. It's bad in excess and it's better to have foils or a cap and not have the chemicals right on your scalp. The experts aren't sure of how much is absorbed through the skin and then into the blood stream (thus why 'they' say to stay away from it while preggo) go give yourself a boost, we all need a little primping from time to time!