While this advance was significant, several hurdles remained. Specifically, synthesizing progesterone in the laboratory was both difficult and expensive. Furthermore, natural progesterone could not be given orally because it is destroyed in the digestive system when ingested in its natural form. In the years that followed, American chemist Russell Marker succeeded in producing progesterone from the roots of wild Mexican yams. Subsequently, in 1949, scientists at the University of Pennsylvania achieved the production of synthetic progestins.
Estrogen works in conjunction with progestin to suppress ovulation, and prevent fertilization.
Continued research led to the development of two synthetic estrogens-mestranol and ethinyl estradiol, both of which can be taken orally. In 1956, Dr. Gregory Goodwin Pincus created the first Pill with government funding and help from birth control advocates Margaret Sanger and Katharine McCormick. It wasn't until four years later, however, that the U.S. Food and Drug Administration approved the first oral contraceptives for marketing in the U.S. Ortho Pharmaceutical introduced its first birth control pill in 1963. By 1965, the Pill became the nation's leading reversible method of contraception. The ensuing decades brought continued pill research, discovery and innovation.