My due date is Dec 3 and based on that my conception date is March 12. I had sex on Feb 26 and again on March 12. I need to know which of these dates could be the correct date i got pregnant. I am confused because I had my LMP on March 7 to March 11 which was a light(spotting)period which I am use to because I have irregular periods. I need to know if i got pregnant as a result of having sex on Feb 26 or on March 12.