Friend is on the pill & is 10 days late for her period, i think she might be pregnant & i don't think she started another pack.what else could it be?

Late period: Suggest subject start taking home pregnancy tests to see if she is pregnant or not.

Lots of things: Pregnancy is certainly a possibility; however, there are other reasons women sometimes miss periods. For example, stress, illness, rigorous exercise, extreme weight loss, thyroid problems can all cause a women to miss periods. Tell your friend to do a home pregnancy test to see if she is pregnant. Best wishes!