He was 83 and had been suffering from congestive heart failure.
The birth control pill, which prevents ovulation -- the release of eggs for fertilization -- has been widely successful since its adoption in the late 1950s, but not all women could use it successfully. Some complained about side effects, such as breakthrough bleeding and depression, while others feared weight gain and cancer. Some women became pregnant because they forgot to take one or more pills.
Segal led a team of researchers at the Population Council who were looking for alternatives that might have fewer side effects, and be less expensive and less susceptible to absent-mindedness. Their first effort, after 24 years of work, was Norplant, a set of six small silicone capsules, each containing a progestin hormone called levonorgestrel.
Implanted in a woman's arm, Norplant blocked pregnancies for five years or longer. It not only prevented ovulation, but also thickened the mucus of the cervix, preventing sperm from entering and fertilizing eggs.
Norplant was approved by the Food and Drug Administration in 1990, and Wyeth Pharmaceuticals began marketing it the following year. The product was immediately dogged by controversy. Some judges ordered women who were abusive to their children to have the device implanted in their arms. Some states tried to give incentives, financial and otherwise, to poor and single women to use the device.
Segal was appalled. He said later that he and his team had been concerned that some governments would use Norplant coercively, but they had been worried about China, not the United States. In a 1990 letter to the Washington Post, he wrote: "Hold everything! Norplant should never be used for any coercive or involuntary purpose. It was developed to enhance reproductive freedom, not to restrict it."
By 1996, more than 50,000 women had filed lawsuits against Wyeth and their physicians, arguing that they had not been adequately warned about such side effects as irregular menstrual bleeding, headaches, nausea and depression -- even though the package label clearly stated that those were potential side effects. Wyeth never lost a court case, but eventually settled with 36,000 women for $1,500 apiece.
The device was withdrawn from the U.S. market in 2002 and is no longer distributed anywhere.
Segal's team subsequently developed a second device, called Norplant II or Jadelle, that consists of two small rods containing levonorgestrel. Although it was approved by the FDA, Jadelle has not been marketed in the United States, but it is used in the U.S. Agency for International Development's overseas programs.
His team also developed an intrauterine device, called Mirena, that releases levonorgestrel continuously and that is sold in the United States, as well as copper-bearing intrauterine devices (IUDs) and contraceptive vaginal rings.
Sheldon Jerome Segal was born March 15, 1926, in Brooklyn, N.Y. He enlisted in the U.S. Navy at the age of 16 near the end of World War II, eventually rising to the rank of lieutenant, junior grade. He served on a troop transport vessel that was sent overseas in anticipation of an invasion of Japan, but it was diverted to Bikini Atoll for nuclear tests when the war ended with the bombing of Japan.
Segal earned a bachelor's degree from Dartmouth in 1947 and a doctorate in embryology and biochemistry from the University of Iowa in 1952. He joined the Population Council in 1956 and stayed there most of his career, except for a stint at the Rockefeller Foundation from 1978 to 1991.
In 1999, he and Elsimer M. Coutilho published the book "Is Menstruation Obsolete?" in which they argued that monthly periods were unnecessary and not medically beneficial -- a concept that has been adopted by many researchers. Segal was also the co-author of "Hormone Use and Male Andropause: A Choice for Women and Men" and the autobiography "Under the Banyan Tree: A Population Scientist's Odyssey."
He is survived by his novelist wife of 48 years, the former Harriet T. Feinberg; three daughters, Amy R. Segal of Newton, Mass., Jennifer S. Madden of Bedford Corners, N.Y., and Laura J. Segal of Watertown, Mass.; and seven grandchildren.