NFP does not change the human body in any way but works in harmony with it. NFP does not have any of the negative side effects that hormonal birth control and intrauterine devices have been shown to have for women. There are research studies indicating that hormonal contraceptives can increase the risk for breast cancer, cervical cancer, blood clots, Crohn’s disease, SLE (lupus), depression, and other health problems. Insertion of an IUD can result in perforation of the uterus. IUDs can also cause altered menstrual bleeding patterns, including irregular and/or heavy bleeding, as well as cramping. Women have a right to know how to avoid such health risks by using NFP.

Additionally, estrogenic substances released into waterways are known to have adverse effects on wildlife, such as causing the feminization of male fish. The estrogen excreted by women taking oral contraceptives contributes to this environmental problem. NFP has no negative effects on the environment.