It as advisable to have Ipill
within 24-72 hours after the unprotected sexual intercourse in this situation. Birth control for few days may not give you any protection. However, if your menses were expected just within few days, the chances of pregnancy
would be very remote as the egg is released 14 days prior to the next menses. Still, safe period is not a very reliable method of birth control and should be reinforced by some reliable method like post coital emergency birth control pill.
Hope this helps you.
Dr. Nishikant Shrotri