No. No reason it should be. Acupuncture is just tiny needles applied to your skin. I'm not a big believer in their efficacy in the first place, but probably it is no harm no foul. They probably don't do that much positive, nor negative either.
No. There are some acupuncture points that are especially good during pregnancy. One of them has the name "beautiful baby ". There are other points that are to be avoided during pregnancy and a good acupuncturist would know that. But yes in general acupuncture can be very helpful for many problems during pregnancy , when a lot of pharmacological medications are to be avoided.