Hello Thanks for writing to us with your health concern. What is the normal length of your menstrual cycle ? Generally, you should start taking Meprate 3 - 4 days before your expected period dates. Then you should continue taking it as long as you do not wish to menstruate. After stopping Meprate, you would have a withdrawal bleed within 5 - 7 days at the maximum. Also, the dosage of Meprate depends on your body weight and a lot of other factors. If you are under 60 kg, then one tablet a day should be taken, else you should take twice the dosage. Also, if it is not an emergency, it is not advisable to meddle with your normal cycles, as it can lead to irregular cycles for a short term. However, it has no long term effects. Meprate when taken correctly and consistently is quite effective in postponement of periods. All the best Please feel free to write in at - http://doctor.healthcaremagic.com/doctors/dr-aarti-abraham/64623 Take care.