Hello, Thanks for writing to us. If you do often unprotected sex, then there is quite chance of pregnancy. Therefore, I suggest her to undergo the home pregnancy test at the earliest to confirm pregnancy. Beside pregnancy, reasons of late period and above clinical features could be hormonal imbalance, over weight/ extreme loss, extra mental stress or anxiety, emotional upset, eating disorder, thyroid problem, PCOD etc. On NEGATIVE test, I suggest her to undergo one USG lower abdomen and hormone test to rule out other underlying causative agent and confirm the diagnosis. Kindly, consult with her local gynecologist and take advice accordingly. She may need to take hormonal pill to induce period. She would control body wt, avoid stress, take healthy low carbohydrate diet with avoidance of fatty food and sleep properly. Be well and take care.