I believe the store management should have handled this more professionally, but honestly I agree with posters who say that if you're pregnant and worried about your baby's health, it makes no sense the you are at a fast food place eating fatty, fried, high-sodium, low nutrition food.

A few gnats are not going to harm you or the baby. In fact, I think they are probably less poisonous than greasy, processed fast food loaded with preservatives.

The store owes you an apology and a refund. Don't be ridiculous and get an 'attorney involved'