Dolores Madrigal, the lead plaintiff in a landmark lawsuit brought by Latina women in California who said they were coerced into unwanted sterilization during childbirth at a Los Angeles hospital in the early 1970s, died on Nov. 9 in Las Vegas. She was 90.

The death, at a hospice facility, was confirmed by her son Oren Madrigal.

Ms. Madrigal was among several hundred Spanish-speaking women who said they were pressured into signing consent forms — written in English — agreeing to have their fallopian tubes tied during cesarean section deliveries. Ten of them filed a federal class action lawsuit against the Los Angeles County-U.S.C. Medical Center in 1975.

The sterilizations occurred amid political hysteria about overpopulation: In 1970, President Richard M. Nixon had established the Commission on Population Growth and the American Future, led by John D. Rockefeller III. The plaintiffs argued that the hospital, which received state and federal funding for family planning programs, was trying to lower the birthrate of Mexican American women — a charge hospital administrators and medical staff denied.

After a bench trial in 1978, Judge Jesse W. Curtis Jr. of U.S. District Court for the Southern District of California ruled against the plaintiffs, writing in his decision that their “ability to understand and speak English is limited,” that the case was “essentially the result of a breakdown in communications” and that “one can hardly blame the doctors.”

Ms. Madrigal’s experience showed otherwise, her attorneys had argued, and ultimately led to state and national reforms, including mandatory waiting periods for the procedure, known as tubal ligation, for women in labor, and requirements that doctors provide patients with consent forms in their native language.