My daughter is taking birth control and has missed her period now 2 days past and has already started her next pill pack. she has taken two pregnancy tests, both negative. she took all her pills correctly so should she trust the tests?

Some normally regular women skim a cycle or two. Many on BC will see a lessening or loss of menses over time. A urine pregnancy test would be positive by 3 wks after conception as this creates chemicals that would turn up in the urine. If the delay passes 60 days with a negative pregnancy test an OBGYN might offer meds to bring on menses if they decide it would be appropriate.