Contraceptives, PostcoitalContraceptives, Postcoital, HormonalCoitusMetrorrhagiaMenstruation-Inducing AgentsContraceptives, Postcoital, SyntheticUterine HemorrhageEthinyl EstradiolContraception, PostcoitalPregnancyDrug Administration ScheduleAntineoplastic Combined Chemotherapy ProtocolsTreatment OutcomeDrug Therapy, CombinationCyclophosphamide