If you do not wish for pregnancy
in the near future, you can go for the pill. Otherwise, you may take progesterone
for up to 20 days without any problem. You will have withdrawal bleeding 2-5 days after stopping the drug. It is not advisable to use medication to advance periods as the results are not always positive. instead, trying for postponement is more effective. The continuation of the medicine depends on the duration of your travel. Also, try to reduce some weight as this is definitely going to help in rectifying the cycle irregularity. Please get further advice from your doctor. Take care.