Hello, Thanks for writing to us. Irregular intake of birth control pills make cycle irregular due to hormonal imbalance. You should take regular pill on proper time to avoid unwanted pregnancy. I suggest you to undergo the home pregnancy test after 2 weeks from last sexual intercourse. Blood test for beta-hCG is more reliable. 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.