Sheldon Segal, a biochemist and embryologist, was best known for his research into and development of several highly effective, long-acting contraceptives. More than 120 million women around the world have used one of the contraceptives developed under Segal’s leadership.
The most notable of these was Norplant, the first contraceptive implant, introduced in 1991, which was seen to be the answer to the main problem of the birth control pill — the possibility that the user would forget to take one. Norplant contains progestin, a synthetic substance that has properties similar to natural progesterone, the female sex hormone involved in the female menstrual cycle and in pregnancy. Norplant is made up of six tiny silicone rods that contain progestin. Implanted under the skin of the woman’s upper arm, where they are left for as long as five years, they slowly release progestin into the body. The progestin thickens the cervical mucous, creating a barrier for sperm, and suppresses ovulation. It also thickens the lining of the uterus, hindering the implantation of a fertilised egg.
Segal also developed the Mirena intrauterine system (IUS), a contraceptive device, inserted into the womb in a similar way to a contraceptive coil, which contains levonorgestrel, a synthetic form of progesterone. Mirena steadily releases the levonorgestrel into the uterus. Levonorgestrel increases thickness of the natural mucus at the neck of the womb, making it more difficult for sperm to cross from the vagina and making the successful fertilisation of an egg less likely. It also prevents the lining of the womb from thickening each month in preparation to receive a fertilised egg. Levonorgestrel may also prevent ovulation.
Sheldon Jerome Segal was born in 1926 in Brooklyn, New York City. He attended the Erasmus Hall High School, Brooklyn and at the age of 16, during the Second World War, he enlisted in the US Navy, rising to the rank of lieutenant. He served in a troopship that was sent to the Pacific for the planned invasion of Japan. When Japan surrendered, his ship was diverted to the Bikini Atoll, in the Pacific, as part of the team participating in America’s nuclear weapon tests.
After leaving the navy, he enrolled at Dartmouth College, Hanover, New Haven, earning a bachelor’s degree in 1947. He then went to the State University of Iowa (now the University of Iowa), receiving his doctorate in biochemistry and embryology in 1952. He was then appointed an assistant professor at the university.
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In 1956 Segal joined the Population Council, New York as assistant medical director of the council’s Centre for Biomedical Research, and in 1963 he was appointed director of the biomedical laboratories. The Population Council aims to improve the wellbeing and reproductive health of current and future generations. In 1978 he left the Population Council to become director of the Rockefeller Foundation’s newly formed division of population sciences and to continue his advocacy for basic and applied research in reproductive biology.
In 1991 he returned to the Population Council as Distinguished Scientist and chairman of the council’s Institutional Review Board. He was also Ella Walker Distinguished Fellow at the Rockefeller Foundation’s Bellagio Study and Conference Centre and an adjunct professor of clinical pharmacology at Weill Cornell Medical College. In 1970 Segal founded the International Committee for Contraception Research (ICCR) to provide a noncommercial, international association for identifying, developing, and testing new contraceptives.
Segal received a number of honours and awards for his contributions to contraceptive development and reproductive health. He was elected a member of the US National Academy of Sciences Institute of Medicine; an honorary member of the Royal College of Obstetricians and Gynaecologists, London; an honorary member of Mexico’s National Academy of Sciences; and an honorary member of China’s Academy of Sciences.
In 1984 he received the United Nations Population Award, given in recognition for his outstanding contributions to increasing awareness of population questions and to their solutions.
He wrote or co-wrote more than 300 scientific papers. His books include: Is Menstruation Obsolete? (co-written with Elsimar M. Coutinho, 1999) and Under the Banyan Tree: A Population Scientist’s Odyssey (2003).
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Segal was athletic, enjoying tennis, running, skiing and sailing. His wife and three daughters survive him.
Sheldon Segal, biochemist and embryologist, was born on March 15, 1926. He died on October 17, 2009, aged 83