Level 1: What is ovulation? The ovulation period is the most fertile period in a woman\’s menstrual cycle. It is usually calculated from the first day of menstruation. The ovulation period is approximately day 14 in a 28-day cycle. This is because ovulation is when mature eggs from the ovaries are released into the fallopian tubes, waiting for fertilization. If a sperm combines with an egg during this time, it will