Thanks for the query.
The possibility of pregnancy
is less according to your history.
If you had intercourse during the non-ovulatory period, the risk will decrease further.
If you had intercourse during ovulatory period, and if you are having any doubt about the contraceptive
methods used, you can go for i pill
within 72 hours of the act.
Remember you should not use I pill frequently, there should be at-least two months gap from pill to pill.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429