Hello... My Girl Friend Is Having Periods Problem For Last

Hello... my girl friend is having periods problem for last two months... she consulted a gyno and the doctor prescribed her a medicine... and asked her to take the medication after 2 weeks... but last night i had a relation with her without any protection and i am afraid that something went wrong... can she take a ipill or she should take the medicine as prescribed by the doctor for normal periods...

Awaiting your response
Thanks and regards