The bases of prophylactic is estrogen and progestational hormone , take for a long time can throw into confusion endocrine balance of the female , cause menstruation to be not moved , can make bust smaller and smaller only so 避孕药的主要成分是雌激素和孕激素，长期服用会打乱女性的内分泌平衡，造成月经不调，这样只会使胸部越来越小。
