Thanks for choosing health care magic for posting your query.
I have gone through your question in detail and I can understand what you are going through.
The fact that she has taken the preventive pills after 64 hours and that too only 4 of them and that the sex was unprotected ones with a possibility that some semen might have landed inside, it is always posible that your girlfriend get pregnant. But the possibility is very low.
Hope that helps
Hope I am able to answer your concerns.
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Wish you good health,
Dr. Srikanth Reddy M.D.