Is it safe to wear high heels while I am pregnant?

Safe in moderation. Depends on what is considered "high heels" in heels, the entire body posture is changed, the severity of the possible ankle sprain could be worse than if not pregnant.
Usually. Reasonable heeled shoes can usually be worn during pregnancy as long as the shoes are comfortable and the women wearing the shoes feel stable in them.
Yes. There is no reason not too, however the further along in pregnancy, the more your center of gravity changes. This could cause loss of balance.