Dr. C. Wayne Bardin, a groundbreaking researcher in reproductive physiology, who was instrumental in the development of long-acting contraceptive methods — like Norplant, Jadelle and Mirena — used by millions of women around the world, died on Oct. 10 at his home in Manhattan. He was 85.

His wife, Beatrice Bardin, confirmed the death without specifying a cause.

An endocrinologist, Dr. Bardin was passionate about finding ways for women to take control of their own health. While working for the nonprofit research organization the Population Council — as director of its Center for Biomedical Research and chairman of its International Committee for Contraception Research — he oversaw clinical trials in the mid-1990s that led to the approval of mifepristone, or RU-486, a synthetic steroid used as part of the so-called “abortion pill” to terminate a pregnancy.

When Dr. Bardin joined the Population Council in the late 1970s, the birth-control pill had been around for nearly two decades, but it provided only short-term contraception; women had to remember to take it regularly. And long-acting contraceptives, like intrauterine devices, or IUDs, which were developed in the early 1900s, were difficult to insert and remove and could have severe side effects. Many women who used them experienced cramps, infections and heavy bleeding.

One IUD, the Dalkon Shield, was linked in the 1970s to incidences of pelvic inflammatory disease and even death, casting a shadow over the entire market.