Pregnancy does affect your hair -- it could alter the growth and loss patterns (many women report losing a lot of hair about three months postpartum), and it can also change oil levels, which then can affect amount of curl and your hair's overall condition. I am not aware, however, of any reasons that would keep you from re-touching your new growth during the second and third trimesters. I have never experienced any negative results by performing either of these services on clients during their pregnancies.

During pregnancy, it is always a good idea to ask the advice of your health care provider regarding chemical services. And it's also wise to try to keep the products off your scalp and skin as much as possible.