In 1952 Gregory Pincus (1903-1967), a biologist working at the Worcester Foundation for Experimental Biology in the United States, demonstrated that a synthetic form of the hormone progesterone, known as norethidrone, inhibited ovulation in rabbits and rats. Norethidrone had been developed a year earlier by Carl DJerassi, a chemist working at the Syntex company in Mexico City. It had initially been created with the aim of producing high concentrations of progesterone to treat menstrual disorders. It had the advantage of being more active than the human hormone, and also of being effective when taken orally. Margaret Sanger, founder of the American Birth Control League, saw the potential of Pincus's work. She enlisted the help of heiress Katharine McCormick, who agreed to fund research to develop a contraceptive pill.
Pincus developed a pill with the aid of gynecologist John Rock (1890-1984), a devout Catholic aiming to improve conception among infertile couples. The resulting pill, combining estrogen and progesterone, worked by fooling the pituitary gland into thinking that a woman is pregnant. The pituitary gland then cuts the output of the FSH and LH hormones, which are essential for egg release. Clinical trials started in Puerto Rico in 1956, and the following year the U.S. Food and Drug Administration approved Syntex's norethidrone. It was passed for contraceptive use in 1960.
"The Pill" has been used by millions of women worldwide, but it has been cloaked with controversy from the start. Critics said it interfered with women's natural cycles, encouraged sexual freedom in unmarried women, and even undermined the social order. Supporters countered that it had the potential to stem poverty, reduce unnecessary deaths, and free women from fear of unwanted pregnancy.
