Are waffles healthy and safe to eat during pregnancy?

Yes. Though a healthy natural low glycemic index carbs will be better on mother and expected baby.
Waffles. Waffles are safe, but as far as healthy - it's relative. They have a lot of carbs and if you have gestational diabetes, they are not the best for you. If you are not diabetic, moderation is the key here as you don't want to gain excessive weight on carbs either as it would be harder to lose it later.
Of course. Be mindful of the calories and consider whole wheat waffles there is no particular risk of most foods during pregnancy.