After protests from scientists and health experts, federal health officials said Thursday it would restore funding for the Women’s Health Initiative, one of the largest and longest research into women’s health to date.

The discovery of WHI and its randomized controlled trials has helped to change medical practices, form clinical guidelines, and prevent hundreds of thousands of cardiovascular diseases and breast cancer.

“These studies represent important contributions to our better understanding of women’s health,” said Emily G. Hilliard, a spokesperson for the Department of Health and Human Services.

“We are currently working to fully recover funding for these important research efforts,” she added. The National Institutes of Health is deeply committed to advancing public health through rigorous gold standard research and is taking immediate steps to ensure the continuity of these studies.”

WHI began in the 1990s Over 160,000 participants were enrolled nationwide when few women were included in the clinical study. It continues to pursue around 42,000 women, Data tracking data on cardiovascular disease and agingweakness, loss of vision, mental health.

Researchers hope to use the findings to learn more about how to maintain mobility and cognitive function and slower memory loss, detect cancer faster, and predict risks for other diseases.

HHS notified research team leaders that it would end the contract for WHI’s regional center in September, but the clinical coordination center based at Fred Hatch Cancer Center in Seattle will be funded until at least January 2026.

Sen. Patty Murray, a Washington Democrat, said shutting down the trial would be “a catastrophic loss for women’s health research.”

Not only has the initiative led to significant advances in women’s health, it also “paved the way for a generation of researchers focused on women’s health. This has been overlooked for a long time and underfunded,” Murray said.

WHI includes many randomized controlled trials, contributing to over 2,000 research papers. However, it is perhaps best known in a study of hormone replacement therapy that suddenly stopped in 2002 after researchers discovered that older women who collected estrogen-progestin combinations experienced a small but significant increase in their risk of breast cancer.

Until then, there was a widespread belief that hormone replacement therapy would protect women from cardiovascular disease. However, the trial found that women were at increased risk of heart attacks, strokes, and clots, despite the combination of hormones reducing colorectal cancer and hip fractures.

Dr. Joan Manson, one of the long-term lead researchers in the study and one of the medical professors at Harvard Medical School and Brigham and Women’s Hospitals, called the announcement of the funding cuts “sadly.”

She was given a statement by National Health Secretary Robert F. Kennedy Jr. about the importance of reducing chronic illnesses in America, and the original decision to cut funds is baffling, she said.

“There is no good example of the scientific impact of research on chronic disease prevention than WHI,” Dr. Manson said.

Lessons learned Hormonal research has resulted in huge savings Researchers discovered this at medical expenses. One study found that between 2003 and 2012, roughly $35 billion was the number of cases of cancer and cardiovascular disease that were avoided. For every dollar spent on WHI, I saved $140.

One randomized trial conducted by WHI saw the effects of a low-fat diet high in fruit and vegetables. Researchers initially found a reduction in ovarian cancer alone, but long-term follow-up showed that this diet also reduces deaths from breast cancer.

Another study of calcium and vitamin D found that supplements provided slight benefits to maintain bone mass and prevent hip fractures in older women, but did not prevent other fractures or colorectal cancer.

Although the findings have affected medical guidelines, we do not currently recommend that all women take supplements regularly.

Participants in the initiative are currently between 78 and 108 years old, and some scientists have acknowledged that there could be discussions to end the trial. However, careful planning is usually given to shut down such a large-scale wide range of research.

“There’s still a lot to learn,” said Garnet Anderson, senior vice president and director of the Department of Public Health Sciences at the Fred Hatch Cancer Center and lead researcher at the initiative.

“Studying 13,000 women at age 90, what are your health needs? How do you live such a long, healthy life?” she said. “I want to know the secrets of success for healthy aging.”

Part of the reasons research began in the 1990s was the lack of information and research on women’s health and there was little evidence underlying clinical recommendations, says Marian Neuhauser, who heads the cancer prevention program at the Fred Hatch Cancer Center and chairs the WHI steering committee.

“Women are half the population,” Dr. Neuhouser said. “However, they were not included in the study. It was mostly male and the results were extrapolated to women.”