Hello..I understand your problem. Period postponing drugs does not normally cause side-effects as it is taken for such a short period of time. However, the  most common side-effects which some women may experience are  rashes, itching, dizziness and headaches, nausea or depression. More serious side effects can include thrombosis or jaundice, fluid retention (which can lead to high blood pressure) and migraines. And the drug dosage for period postponing is higher than the normal dosage used for monthly contraception. Period postponing tablets are not meant for long use.. But taking them for consecutive two months just for a week wouldnt harm you..If you are still confused and not sure about you can consult a gynecologist on the same.