One of the side effects of birth control pills is the temporary lack of ovulation/menstruation after coming off the pill. Women also experience irregular vaginal bleeding (spotting) until ovulation is re-established. During this period of time without ovulations, it is not possible to conceive. This period usually lasts several months. Most women establish ovulation and regular cycles in a period of 6 months after taking oral contraception. The maximum waiting period, however, is 2 years. After that time, doctors may prescribe ovulation inductors to promote conception.