' Skip To Content
The Pill | Article

The Boston Pill Trials

Worcester Foundation for Biomedical Research

When birth control advocate Margaret Sanger asked Gregory Pincus to come up with a birth control pill, he knew one of the hardest parts of the process would be the large-scale human trials necessary for approval by the U.S. Food and Drug Administration (FDA). Pincus was a scientist, not a clinical physician, and was barred from conducting human trials. Significant legal restrictions on birth control devices made testing the drug virtually impossible. Pincus would need to find a partner who was willing to take on a controversial project and who would be able to provide the study with a source of volunteers for the trials.

A Medical Partner
In a stroke of good fortune, Pincus found just the doctor working a mere forty miles down the road from his Shrewsbury, Massachusetts, lab. At a medical conference in the early 1950s, Pincus ran into an old acquaintance, Dr. John Rock. To his utter astonishment, Rock was already testing progesterone on his infertile female patients.

Helping Women Conceive
At the same time Pincus had been giving a synthetic version of the hormone progesterone to rabbits and rats to inhibit ovulation, Rock was giving women the hormone to enable them to become pregnant. Rock worked with women who had no identifiable cause of infertility yet were unable to conceive a child, placing these patients on a daily regimen of progesterone and estrogen for several months. He theorized that the drug would allow their bodies to "rest" from ovulation. Then, after stopping treatment, his hope was that the reproductive organs would "rebound" more vigorously and enable his patients to conceive. Rock's instincts proved correct. After Rock administered the therapy to 80 patients, 13 of them conceived within four months of finishing the hormone treatments. In the nascent field of infertility treatment, statistics such as these were considered remarkable.

When Rock reported on his findings, the medical world took immediate notice of what it called the "Rock Rebound." But few were interested in the most striking aspect of the experiment -- the suspension of ovulation with the use of hormones. Rock had crossed the great divide between animal and human testing, and Pincus soon asked him to collaborate on human trials for the Pill. Although he was a devout Catholic, Rock was also a firm believer in birth control. He agreed to work on the project.

Historic Drug Trials
Under the guise of fertility research, Pincus had found a way to test the contraceptive powers of progesterone on women and sidestep Massachusetts' rigid anti-birth control laws. Rock was intrigued by Pincus' experiments with progesterone alone, and Rock agreed to test just the single hormone on his patients. Although Pincus and Rock camouflaged the true purpose of their study, the tests would be historic: the first human trials of an oral contraceptive.

In 1954 Rock began his first tests of synthetic oral progesterone on a group of 50 infertility patients at his clinics. Although the women volunteered to participate, another group of patients were given the experimental drug without their direct consent. The Pill team also tested the oral contraceptive on 12 female and 16 male psychiatric patients at Worcester State Hospital. The study's goal was to test the long term effects of the drug on the reproductive system. It provided useful information during the early stages of the Pill trials. While Pincus did receive permission from the patient's relatives, and the trials did conform to medical standards of the day, under today's standards for human drug trials the tests would be considered unethical.

Making the Treatment "Natural"
In his previous study, Rock had given women daily injections of progesterone which made them cease menstruation for the entire three- to four-month period they were on the treatment. For this new trial, Pincus suggested that Rock adopt a 20-day regime that would stop ovulation and still allow women to menstruate every month. Pincus hoped that with this regimen that the drug would be viewed as not interfering with a woman's normal reproductive functionsr. Rock jumped at the idea. Since this modified regimen mimicked the reproductive cycle, Rock believed the Catholic Church might consider the process "natural" — and therefore an acceptable form of birth control.

A Turning Point
Month after month Rock carefully checked whether the women in the trial were ovulating. Finally the results came in. Not one of the fifty women ovulated during their time on the oral progesterone. The Pill team was ecstatic. The oral contraceptive was not only effective, but the effects of the drug were temporary, thus eliminating any fear that the Pill would have a permanent sterilizing effect.

In early 1956 Rock told the world about his clinical trials at a conference of scientists involved in hormone research. Although he avoided any direct discussion of the drug as a deliberate contraceptive, everyone listening knew he was talking about a pill that could control women's fertility. The Pill would still have to undergo large-scale human trials before it could receive FDA approval, but the Boston trials were a huge turning point. It would only be four more years until women could walk into their doctor's offices and get prescriptions for the Pill.

Support Provided by: Learn More