Delayed Period After Birth Control Pill Use: What to Know

Question
Hi, my girlfriend has been taking birth control by way of the pill for three months. Instead of taking the sugar pills at the time in which she is supposed to have her period she just continued taking the birth control pills. This continued for three months. The doctor said it was ok to do this for six months at the most. Well she stopped on the third month to have her period (which i understood would only take three or four days). Its about fifteen days later and she still hasnt had it yet, she never missed a pill the whole time and took it within the same time period every single day (within 2 hours). I was wondering if she could possibly be pregnant or if she has to wait the extra three weeks to wait for the extra pills to run out her system before she has her period?

Answer
She needs to take a pregnancy test to make sure that she isn't pregnant. She probably isn't, it sometimes takes a while for the period to get back on track, especially since she skipped her period. As long as she has been taking the pill at the same time everyday - she is probably okay.
Dianna