Can I use a tourist visa to enter the United States during pregnancy?

It depends on your actual situation. If you apply for a trip to the United States with an obvious belly, the visa officer may not believe you and think you are dishonest. If the applicant originally had the idea of having children in the past, it is recommended to sign honestly. If your stomach is not obvious or you can't see it at all, of course, you should apply according to ordinary travel. Easy is not easy, depending on your original situation.