###Human: Is it possible to get pregnant from having sex immediately after periods? ###Assistant: Hi. The days of your menstrual cycle start counting at day one of menstruation. So, you were on day 8 that night. Fertile days are considered from 11 to 16th in a regular menstrual cycle (this means you always have your period every 28 to 32 days). You have a very low probability of being pregnant, but not a zero probability. My suggestion at this point is to wait for day 5 to 7 from the day you had your encounter to take a urine pregnancy test since right know it is not useful taking any medication such as the day after pill and doing a pregnancy test before day seven can be falsely negative.