Six months pregnant seems like bad timing for hair color, not only because of chemical probs, but also because once the baby is born you are probably not going to want to have to deal with root redos, etc. My suggestion would be to spend the money instead on a really good haircut. No chemicals, and the advantage of a good haircut is not only style but how long it lasts. If you like the cut, go again in 5 mo., and it should last you until you can get a grip.

My method of finding a good haircutter is to politely accost any good natural haircut I see walking around, at the market, for instance, and ask who her hairdresser is...look especially for styles you think would look good on you or fit your hair type and be easy to care for, not dependent on elaborate sets, fat rollers, etc.