Pioneering Studies of the “Morning-After” Pill

Drs Morris and van Wagenen tested Diethylstilbestrol usage for years

2011 Abstracts

Yale School of Medicine produced the first proof-of-concept study on the viability of a “morning-after” pill for human use. This study was a result of a fruitful collaboration between a pair of Yale scientists, Drs. John M. Morris and Gertrude van Wagenen, who sought a non-abortion, post-coital contraceptive. They tested a variety of hormones, hormone-based synthetic drugs, and other compounds in monkeys in an effort to uncover a compound that was non-toxic but highly effective. Unfortunately, although they were unable to identify such a drug, their initial studies inspired other scientists to further pursue the concept of a “morning-after” pill, leading to the development of Food and Drug Administration (FDA)-approved emergency contraceptives.

… “Morris and van Wagenen had shown that diethylstilbestrol, ethinyl estradiol, and mestranol prevented implantation in rabbits very efficiently. These same compounds were ineffective in preventing implantation in monkeys at the same dosage, but when the concentration was increased and treatment given orally or by intramuscular injection for 6 days, they were able to prevent ovum implantation. This set the stage for a preliminary clinical trial that showed that 50 mg of diethylstilbestrol or 0.5 mg of ethinyl estradiol for 4 to 6 days after coitus was effective in preventing pregnancy. Though this study was not statistically significant, it represented the first time that prevention of implantation was demonstrated in humans.

Unfortunately, diethylstilbestrol and ethinyl estradiol have several side effects, such as nausea and breast soreness, which are common to estrogenic compounds. An ideal post-coital contraceptive would be non-toxic, non-teratogenic, highly effective against implantation of the ovum, and exhibit few side effects. In an effort to find such compounds, Morris and van Wagenen turned to … ” …


  • Pioneering Studies of the “Morning-After” Pill, The Yale journal of biology and medicine, NCBI PubMed PMCID: PMC3117403, 2011 Jun.
  • Image credit villagevoice.

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