Elizabeth Maplesden Ramsey (1906-1993)

By: Kaitlin Smith

Elizabeth Maplesden Ramsey

Physician and pathologist Elizabeth Maplesden Ramsey was a member of the Carnegie Institution of Washington (CIW) for thirty-nine years. The affiliation began in 1934, when Ramsey discovered what was assumed to be the youngest-known embryo at the time, and donated it to CIW’s massive embryo collection. After studying embryos, Ramsey focused her research on placental circulation in primates.

Ramsey was born to Grace Keys and Charles Cyrus Ramsey on 17 February 1906 in New York City. Ramsey received her Bachelor of Arts from Mills College in Oakland, California, in 1928. Immediately following graduation, Ramsey studied at the University of Hamburg for a year. Upon her return to the US, she went to medical school at Yale University and earned her MD from Yale in 1932.

While doing her residency in pathology at a New Haven, Connecticut, hospital in 1934, Ramsey made an unexpected discovery that would change her career. During her first autopsy on a young female, Ramsey found a tiny speck of tissue in the uterus. Upon close examination, Ramsey determined that the structure was a small embryo and donated it to the Carnegie Institution of Washington (CIW) Department of Embryology in Baltimore.

The donation of embryos that would otherwise be discarded had become common practice by 1932. A mass collection of embryos had been underway since Franklin Paine Mall became director of the Department of Embryology of CIW (1913–1917). By 1916, hundreds of embryos had been collected from over five hundred persons and were in the possession of Mall’s department. Ramsey’s embryo was determined to be just fourteen days old: the youngest embryo so far collected. Ramsey went against the usual practice of naming embryo after the discoverer and chose to name it the “Yale Embryo.”

The donation of the Yale Embryo was significant because it added a long–sought-after piece to the chronological model of embryonic development. Ramsey herself admitted that finding the embryo guaranteed her admission to the Carnegie Institution. Her relationship with the CIW began after her embryo donation, when she commuted from the District of Columbia to Baltimore as a guest investigator to study the Yale Embryo with leading embryologists George W. Corner, Carl Hartman, Chester H. Heuser, and George Streeter. The group studied over 600 embryos, making cross sections of them for morphological observation. Ramsey remained a guest investigator at the Carnegie Institution from 1932 to 1949 apart from time spent during World War II as Assistant Chief of the Office of Medical Information of the National Research Council.

In 1949 Ramsey was appointed research associate and remained in the position until 1951 when she was promoted a staff member of placentology and pathology. Ramsey was also employed by George Washington University as associate pathologist and professional lecturer. She was the official curator of CIW’s embryo collection until her retirement in 1971.

During her time at CIW, Ramsey drifted from the study of human embryology to placental circulation. She used primates as models for the study of uteroplacental vasculature, by which the maternal blood is kept separate from the fetus. Through the use of x-ray films and cineradiography, Ramsey was able to track the circulation of maternal blood in monkeys. Her findings helped to understand many pregnancy-related problems including “abruptio placentae,” a premature separation of the placenta from the uterus. She became a sought-after lecturer and published over a hundred articles.

Elizabeth Ramsey died in 1993, twelve days after the death of her husband Hans to whom she was married for fifty-nine years. Ramsey left behind a scientific legacy for which she received many honors. The American College of Obstetricians and Gynecologists gave her a Distinguished Service Award and named her to its Hall of Fame. The Society for Gynecological Investigation presented Ramsey with a Distinguished Scientist Award. She was an honorary fellow of the American Gynecological and Obstetrical Society. Ramsey served on the Dean’s Council of Yale Medical School, and, as her interests were broad, also served as a board member of the National Symphony Orchestra and the National Cathedral Choral Society.


  1. Harvey, Joy, and Marilyn Ogilvie. “Ramsey, Elizabeth Maplesden.” In Biographical Dictionary of Women in Science 2, eds. Joy Harvey and Marilyn Ogilvie, 1071–72. New York: Routledge, 2000.
  2. Longo, Lawrence D., and Giacomo Meschia. “Elizabeth M. Ramsey and the Evolution of Ideas of Uteroplacental Blood Flow and Placental Gas Exchange,” European Journal of Obstetrics & Gynecology and Reproductive Biology 90 (2000): 129–33.
  3. Maher, Brendan. “The ‘Yale Embryo’ circa 1934.” The Scientist, February, 2007.
  4. Maienschein, Jane, Marie Glitz, and Garland E. Allen, eds. Centennial History of the Carnegie Institution of Washington. Vol. 5, The Department of Embryology. Cambridge: Cambridge University Press, 2004.
  5. Morgan, Lynn M. Icons of Life: A Cultural History of Human Embryos. Berkeley: University of California Press, 2009.
  6. Wynn, Ralph M. “Elizabeth M. Ramsey (1906-1993),” Placenta 15 (1994): x–xi.


How to cite

Smith, Kaitlin, "Elizabeth Maplesden Ramsey (1906-1993)". Embryo Project Encyclopedia ( ). ISSN: 1940-5030 https://hdl.handle.net/10776/2016


Arizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia.

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