Study the question before you write it. Apparently, you imagine taking hormonal pills as a one-off action, unambiguously guaranteeing a positive result (take it orally before association and drink it with water, and there are no problems). It is not so. Contraceptives are drunk courses with strict observance of the regime. And changing the balance of hormones in the body is a completely different order of intervention than wearing a removable, easily removable hood for a few minutes.
Why study this? They and abortion are presented as a spark on the stomach, well, and the greenery may be for disinfection. It is more comfortable to live.