The type of contraception that works because ovulation is prevented is the birth control pills. Ovulation is when the egg that has left from the ovaries and moved into Fallopian tube, that lastly moves into the uterus, which is the women,s most fertile time of the month when the egg is in the uterus it waits to be fertilized, and when it is not fertilized it is released which leads to periods. Ovulation occurs 14 days after the first day of the menstrual cycle.