What would happen if yu were pregnant an took a birth control pill with an alcohol beverage?

The alcohol, assuming it was a casual drink and not a bottle of pure grain alcohol is not a worry.

If you are asking about some sort of interaction with the alcohol and the Birth Control pill - again not a worry. There is no counter indication for birth control pills and alcohol. In fact if you are going to consume alcohol, birth control pills are a good choice.

The intent of birth control pills in general is to make your body believe you are already pregnant so that you don't get pregnant "again". You should not take them your entire pregnancy because it is tampering with your hormones and pregnancy involves enough of those on its own.

If you followed your normal dosing because you didn't realize you were pregnant you are most likely still safe. Talk to your doctor.

There is a "cocktail" sort of prescription that was used as a "morning after" regime to prevent pregnancy if you forgot to take your normal dosage. It would NOT terminate a pregnancy but would PREVENT one.

If your worry is that you have done something to harm your pregnancy the chances are slim to none assuming it was a single pill and a single drink.

All things in moderation and love your life!