No or less frequent placebos
If the pill formulation is monophasic, meaning each hormonal pill contains a fixed dose of hormones, it is possible to skip withdrawal bleeding and still remain protected against conception by skipping the placebo pills altogether and starting directly with the next packet. Attempting this with bi- or tri-phasic pill formulations carries an increased risk of breakthrough bleeding and may be undesirable. It will not, however, increase the risk of getting pregnant. Starting in 2003, women have also been able to use a three-month version of the pill. Similar to the effect of using a constant-dosage formulation and skipping the placebo weeks for three months, Seasonale gives the benefit of less frequent periods, at the potential drawback of breakthrough bleeding. Seasonique is another version in which the placebo week every three months is replaced with a week of low-dose estrogen. A version of the combined pill has also been packaged to eliminate placebo pills and withdrawal bleeds. Marketed as Anya or Lybrel, studies have shown that after seven months, 71% of users no longer had any breakthrough bleeding, the most common side effect of going longer periods of time without breaks from active pills. While more research needs to be done to assess the long term safety of using COCPs continuously, studies have shown there may be no difference in short term adverse effects when comparing continuous use versus cyclic use of birth control pills.
In July 1961, Searle finally began marketing Enovid 5 mg (5 mg noretynodrel and 75 µg mestranol) to physicians as a contraceptive.Although the FDA approved the first oral contraceptive in 1960, contraceptives were not available to married women in all states until Griswold v. Connecticut in 1965 and were not available to unmarried women in all states until Eisenstadt v. Baird in 1972.The first published case report of a blood clot and pulmonary embolism in a woman using Enavid (Enovid 10 mg in the U.S.) at a dose of 20 mg/day did not appear until November 1961, four years after its approval, by which time it had been used by over one million women. It would take almost a decade of epidemiological studies to conclusively establish an increased risk of venous thrombosis in oral contraceptive users and an increased risk of stroke and myocardial infarction in oral contraceptive users who smoke or have high blood pressure or other cardiovascular or cerebrovascular risk factors. These risks of oral contraceptives were dramatized in the 1969 book The Doctors Case Against the Pill by feminist journalist Barbara Seaman who helped arrange the 1970 Nelson Pill Hearings called by Senator Gaylord Nelson. The hearings were conducted by senators who were all men and the witnesses in the first round of hearings were all men, leading Alice Wolfson and other feminists to protest the hearings and generate media attention.