Hello and welcome to HCM. Thank you for your query. First of all, as you have had a problem of irregular periods since your menarche, then we should further investigate to find the cause. And pregnancy will have to be ruled out once again. The best option would be to take a home pregnancy test kit, and use it 2 weeks after your last sexual intercourse. Using this with an early morning urine sample would be most accurate. Meprate is a hormone and will support pregnancy if it does take place. It will not prevent pregnancy and will not lead to pregnancy (just by taking the pill). I would also advice you to discuss the initiation of birth control pills, which will help in regularizing your periods. Please find the cause (I am assuming endometriosis, due to meprate), after a detailed discussion with your doctor. This is very important. Also, was an ultrasound examination conducted, if yes, then please follow them up with regular intervals, and if not, I recommend this at the earliest. As long as you are using effective contraceptive methods, then you should not get pregnant until you wish to. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you. Best wishes.