The chances of pregnancy when having sex 3 days after menstruation depend on the women’s menstrual cycle and the time of menstruation, as follows: 1. The menstrual cycle is 30 days: If a woman’s menstruation is within three days of clean ovulation, the chances of pregnancy will be very high if she has intercourse without contraception. If not within the ovulation period, the chances of pregnancy will be very low. Because the 16th day of menstruation is the day of ovulation and the 10th-20th day is the ovulation period; 2. The menstrual cycle is less than 30 days: for example, about 25-26 days, the menstrual period is within 5-6 days or 7 days, three days after the clean menstruation is in the time close to the ovulation day, if not contraception then the chance of pregnancy is very high; 3. The menstrual cycle is long: for example, 40-50 days or even 2 months, the menstrual period is within 5-7 days If the period is three days after the clean period is still in the safe period, the chance of pregnancy is relatively low if you have intercourse without contraception.