Hey mama, yes pwede naman mag-color ng buhok habang buntis, pero mas safe kung hintay mo na lang ang second trimester when the baby's organs are na fully formed na, maraming kaibigan ko na nag-color pa rin throughout pregnancy pero they were extra careful sa ventilation at hindi naman sila nag-worry. Better to chat with your OB about it para sigurado especially kung may specific health concerns ka, pero generally okay lang sya kung safe ang gamitin like ammonia-free dyes or better yet mag-highlight ka na lang instead ng full color kasi mas minimal contact sa scalp. Congrats sa pregnancy, mommy!