Women with regular menstruation and a 28-day menstrual cycle will not get pregnant on the seventh day of menstruation because sperm can survive in a woman’s body for 72 hours and eggs can survive for 24 hours, which is three days before ovulation and one day after ovulation, which is the time when it is easy to get pregnant. For women with a 28-day menstrual cycle, the approximate day of ovulation is around the fourteenth day of menstruation, so having intercourse on the seventh day of menstruation will not result in pregnancy. For women with short menstrual cycles, such as 22 or 23 days, intercourse on the seventh day of menstruation is very likely to result in pregnancy. If a woman with irregular periods or short menstrual cycles does not want to get pregnant, she should use contraception after her period clears.