Birth Control Switch: Risk of Pregnancy After Improper Transition?

Question
My daughter was on Kariva and had problems with her skin breaking out, so her Dr. prescribed Loestrin.  Here is the problem, she had taken two weeks of the Kariva and did not finish the pack.  She started taking the loestrin the next day.  She now has one active week left, and she had unprotected sex yesterday.  I am concerned that swithing them wrong could get her pregnant. Could she get pregnant?

Answer
Hey,


Wow, your daughter talks to you about stuff like that? That's amazing.
I think it would be possible for her to become pregnant, because reading about those particular pills, you're supposed to use condoms when first starting to use it, as so her body might not have adjusted to the new pills on time.

However, it is unlikely, as having taken the pill for that long, she probably is still protected.

Diana