 [ Symptoms ] me and my boyfriend had sex early friday morning on my 18th cycle day will there be a chance i will become pregnant [ Disease ] here is a link to a slideshow about fertility and ovulation that i think you will find very helpful it states while the exact timing of ovulation can vary on average it happens between day 11 and 21 of your cycle a brain hormone called luteinizing hormone lh surges triggering the release of the egg that is most ripe at the same time your cervical mucus changes to a slippery egg white consistency to help sperm make their way to the egg  so there is a chance that you could be pregnant if your ovulation cycle fits this pattern the webmd answers staff