Birth Control Pills Are Tested in Puerto Rico Summary

  • Last updated on November 10, 2022

Gregory Goodwin Pincus directed the first large-scale test of the birth control pill in Puerto Rico, paving the way for worldwide use of a safe, effective contraceptive.

Summary of Event

Margaret Sanger was an ardent crusader for birth control and family planning. For decades, she traveled throughout the United States, campaigning for the legalization of contraception. Although she lectured on the use of the condom, diaphragm, and rhythm methods of birth control, she knew that these methods were cumbersome and often ineffective. Deciding that a foolproof contraceptive was necessary, Sanger met with her friend, the wealthy socialite Katharine Dexter McCormick. Progestin Contraception Birth control pills [kw]Birth Control Pills Are Tested in Puerto Rico (Apr., 1956-1957) [kw]Pills Are Tested in Puerto Rico, Birth Control (Apr., 1956-1957) [kw]Puerto Rico, Birth Control Pills Are Tested in (Apr., 1956-1957) Progestin Contraception Birth control pills [g]Caribbean;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] [g]West Indies;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] [g]United States;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] [c]Health and medicine;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] [c]Science and technology;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] [c]Women’s issues;Apr., 1956-1957: Birth Control Pills Are Tested in Puerto Rico[05160] Pincus, Gregory Goodwin Chang, Min-Chueh Rock, John García, Celso-Ramón Rice-Wray, Edris McCormick, Katharine Dexter Sanger, Margaret

A 1904 graduate in biology from the Massachusetts Institute of Technology, McCormick had the knowledge and the vision to invest in biological research. Sanger persuaded her to invest in research to prevent pregnancy. Sanger arranged a meeting between McCormick and Gregory Goodwin Pincus, head of the Worcester Institutes of Experimental Biology Worcester Institutes of Experimental Biology . Pincus had been directing laboratory studies on several aspects of reproductive physiology. After listening to Sanger’s pleas for an effective contraceptive and McCormick’s offer of financial backing, Pincus agreed to focus his energies on finding a pill that would prevent pregnancy.

Pincus organized a team to conduct research on both laboratory animals and humans. The laboratory studies were conducted under the direction of Min-Chueh Chang, a Chinese-born scientist who had been studying sperm biology, artificial insemination, and in vitro fertilization. The goal of his research was to see whether pregnancy might be prevented by manipulation of the hormones usually found in a woman. It was already known that there was one time when a woman could not become pregnant—when she already was pregnant.

In 1921, Ludwig Haberlandt Haberlandt, Ludwig , an Austrian physiologist, had transplanted the ovaries from a pregnant rabbit into a nonpregnant one. The latter failed to produce ripe eggs, showing that some substance from the ovaries of a pregnant female prevents ovulation. This substance was later identified as the hormone progesterone Progesterone by George W. Corner Corner, George W., Jr. , Jr., and Willard M. Allen Allen, Willard M. in 1928. If progesterone could inhibit ovulation during pregnancy, maybe progesterone treatment could prevent ovulation in nonpregnant females as well. In 1937, this was shown to be the case by scientists from the University of Pennsylvania, who prevented ovulation in rabbits by injections of progesterone.

The high cost of progesterone prevented medical exploitation of this finding for humans. Not until 1951, when Carl Djerassi Djerassi, Carl and other chemists devised inexpensive ways of producing progesterone Hormones;synthesis in the laboratory, was serious consideration given to the medical use of progesterone. The synthetic progesterone, known as a progestin, had a chemical structure with even greater clinical activity than the natural hormone.

In the laboratory, Chang tried more than two hundred different progesterone and progestin compounds, searching for one that would inhibit ovulation in rabbits and rats when given to them in their food. Finally, two compounds were chosen, progestins derived from the root of a wild Mexican yam. Pincus arranged for clinical tests to be carried out by Celso-Ramón García, a physician, and John Rock, a gynecologist. Rock was a devout Catholic who, in 1936, had opened the first clinic to teach the so-called rhythm method of birth control to Catholic women.

Before meeting with Pincus, Rock was experimenting already with natural progesterone as a treatment for infertility. It was thought that in some women infertility was caused by insufficient progesterone. Rock hypothesized that three months of progesterone treatment would strengthen these women’s uteruses and oviducts, making pregnancy more likely when the treatment was discontinued. The treatment was effective in some women but required that large doses of expensive progesterone be injected daily.

Rock was hopeful that the synthetic progestin that Chang had found effective in animals would be helpful in infertile women as well. With García and Pincus, Rock treated another group of fifty infertile women with the synthetic progestin for three months. After treatment ended, seven of these previously infertile women became pregnant within half a year. In this group, however, García, Pincus, and Rock made an additional observation. They took several physiological measurements of the women while they were taking the progestin and were able to conclude that ovulation did not occur while the women were taking the progestin pill.

This somewhat indirect method of testing the ability of progestin to inhibit ovulation had its basis in one of Sanger’s failures. In Massachusetts, it was still illegal to provide contraceptive aids. García, who had a position at the University of Puerto Rico, tried a similar study on a group of twenty presumably fertile medical students. These women failed also to ovulate during treatment.

Having showed that the hormone could effectively prevent ovulation in both animals and humans, the investigators still had several problems to solve: the side effects that might occur in women using progestins for a long time; whether women would find progestins an acceptable way to prevent conception; whether it would be effective and reliable over the long term; and whether women would remember to take the pill, day after day, for months or even years. To solve these problems, the birth control pill needed to be tested on a large scale, with many women taking it for several months.

After considering the legal ramifications of testing it in Maryland, as well as considering several other countries, Pincus finally decided to conduct the first large-scale test in Puerto Rico. Through García, he already had several contacts there. The social climate in Puerto Rico was more tolerant of contraception than on the mainland. The crowded island people knew the pressure of population growth, and about 20 percent of women resorted to legal sterilization as a way to limit their family size. In addition, testing progestin in Puerto Rico would keep it out of sight of the anti-birth-control activists in Massachusetts.

The test started in April of 1956. Edris Rice-Wray, a physician, was responsible for the day-to-day management of the project. As director of the Puerto Rico Family Planning Association Puerto Rico Family Planning Association , she had seen firsthand the need for a cheap, reliable contraceptive. The women she recruited for the study were married women from a low-income population living in a housing development in Río Piedras, a suburb of San Juan. Word spread quickly, and soon women were volunteering to take the pill that would prevent pregnancy. In the first study, there were 221 women who took a pill containing 10 milligrams of progestin and 0.15 milligram of estrogen. (The estrogen was added to help control breakthrough bleeding.)

Results of the first large-scale test were reported in 1957. Overall, the pill proved highly effective in preventing conception. None of the women who took the pill according to directions became pregnant in that test, and most women who wanted to get pregnant after stopping the pill had no difficulty. Nevertheless, 17 percent of the women had some unpleasant reactions, such as nausea or dizziness. The scientists believed that these mild side effects, as well as the one death from congestive heart failure, were unrelated to the use of the pill.

Even before the final results were announced, additional field tests were begun by García in Haiti, by Rice-Wray in Mexico, by Adeline Pendleton Satterthwaite in Humacao, Puerto Rico, and by Edward T. Taylor and Henry L. Olson in Los Angeles. In 1960, the Food and Drug Administration Food and Drug Administration (FDA) approved use of the pill developed by Pincus and his collaborators as an oral contraceptive.


The pill, as it was called, was not without its drawbacks. From the earliest trials, some doctors were concerned about the prolonged use of hormones by normal, healthy women. For the average woman, however, the advantages were more obvious. The pill was more effective and easier to use than other birth control methods. It did not interfere with sexual intercourse and did not influence subsequent pregnancies. Most important, the birth control pill was a contraceptive that a woman could control herself, without needing to rely on her partner to take precautions. Within two years of approval by the FDA, more than a million women in the United States were using the pill.

Within a few years, increasing numbers of problems were reported in pill users, particularly problems of the circulatory system. In general, however, these problems were discussed at medical conferences and the information was not made known to the women using the pill. The prevailing attitude of most doctors at the time was that people are not able to make informed decisions about medical matters. A growing consumer movement in the 1960’s had repercussions in the field of women’s health. Women began protesting their medical treatment, and Congress held hearings to determine whether women were being misinformed about possible side effects from taking the pill. In 1970, the FDA required drug companies to include information about possible adverse effects in the packages of the pill.

Under pressure from the public, pharmaceutical companies sponsored additional research into the circulatory disorders found in some women. When these were found to be related to the high estrogen content in the pill, these were reformulated to contain much lower amounts of hormone.

New contraceptives were developed in the 1960’s and 1970’s, but the birth control pill remains the most widely used method of preventing pregnancy. More than 60 million women use the pill worldwide, although women who smoke or who are more than thirty-five years old are dissuaded from using the birth control pill.

The greatest impact of the pill has been in the social and political world. Before Sanger began the push for the pill, birth control was regarded often as socially immoral and often illegal as well. Women in those post-World War II years were expected to have a lifelong career as a mother to their many children. With the advent of the pill, a radical change occurred in society’s attitude toward women’s work. Women had more freedom to work and enter careers previously closed to them because of fears that they might get pregnant. Women could control more precisely when they would get pregnant and how many children they would have. The women’s movement of the 1960’s—with its change to more liberal social and sexual values—gained much of its strength from the success of the birth control pill.

Within a few years, public opinion had been inalterably changed. In 1967, Massachusetts finally liberalized its anti-birth-control law. While the birth control pill developed by Pincus is not the best method of birth control for all couples, the success of the pill made birth control an accepted fact for the vast majority of people. Progestin Contraception Birth control pills

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Djerassi, Carl. The Politics of Contraception: The Present and the Future. San Francisco: W. H. Freeman, 1981. Analysis of the advantages and disadvantages of the pill. Includes selections from Senate hearings on the safety of the pill. Future prospects in contraception for males and females are discussed. The final chapter, “The Chemical History of the Pill,” provides valuable insights into Djerassi’s work, including a clear explanation of the chemistry of the pill.
  • citation-type="booksimple"

    xlink:type="simple">_______. This Man’s Pill: Reflections on the Fiftieth Birthday of the Pill. New York: Oxford University Press, 2001. An idiosyncratic personal narrative is used to organize a history of the first fifty years of oral contraception. Index.
  • citation-type="booksimple"

    xlink:type="simple">Douglas, Emily Taft. Margaret Sanger: Pioneer of the Future. Garrett Park, Md.: Garrett Park Press, 1975. A good biography of Margaret Sanger, from her earliest exposure to the problems of population growth as a young nurse, to her later success in encouraging Pincus to develop a birth control pill. Her friendships with the world’s leaders make fascinating reading.
  • citation-type="booksimple"

    xlink:type="simple">Hartmann, Betsy. Reproductive Rights and Wrongs: The Global Politics of Population and Contraceptive Choice. New York: Harper & Row, 1987. Argues that women’s health has been sacrificed by those who make the pill, neglecting other methods of contraception. Especially critical of oral contraceptive use in developing nations, where medical monitoring of side effects is limited. While not a universally accepted viewpoint, this is a well-researched summary of some criticisms of the oral contraceptive.
  • citation-type="booksimple"

    xlink:type="simple">McLaughlin, Loretta. The Pill, John Rock, and the Church. Boston: Little, Brown, 1982. An exceptionally well-researched biography of John Rock by a journalist who does not disguise her adulation of the doctor. Includes biographical material on Miriam Menkin, whose work with Rock has been largely ignored. Rock’s struggle with the Catholic Church is described vividly.
  • citation-type="booksimple"

    xlink:type="simple">Marks, Lara V. Sexual Chemistry: A History of the Contraceptive Pill. New Haven, Conn.: Yale University Press, 2001. Details both the social need for and effects of the birth control pill and the scientific process behind its invention. Bibliographic references and index.
  • citation-type="booksimple"

    xlink:type="simple">Pincus, Gregory. The Control of Fertility. New York: Academic Press, 1965. Dedicated to McCormick, Pincus summarizes his work on the pill. A somewhat technical compilation of research in early years of development of the oral contraceptive, including both animal and clinical work. Although fairly dated scientifically, it is a good source for understanding the research that Pincus conducted.
  • citation-type="booksimple"

    xlink:type="simple">Seaman, Barbara, and Gideon Seaman. Women and the Crisis in Sex Hormones. New York: Rawson, 1977. As women’s health activists, the authors believe strongly that women were insufficiently warned of the effects hormones have on the body. Includes a history of oral contraceptive development. An earnest plea for less reliance on the pill by women.

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