There are four phases in the female cycle: menstruation, the post-menstrual phase, ovulation, and finally the pre-menstrual phase. In the ovulation phase, hormones stimulate the ovary to release a mature egg. During ovulation, the mature egg travels down the fallopian tube from the ovary into the uterus. At any time during this journey, the sperm can fertilize an egg, which could then be implanted in the uterus. If that happens the woman or girl gets pregnant. Read more about the menstrual cycle in our blog post “Ride that cycle! Periods 101”.