Last week’s results from the nation’s biggest hormone study suggest many of the 6 million American women who use an estrogen-progestin combination should quit.

Dr. Steven Lee of West Atlanta Women’s Health in Smyrna advised women not to panic. “The decision is going to have to be individualized based on their risk factors,” he said.

If you’re using the hormone combination in hopes it will protect your heart, definitely quit, said Dr. Jacques Rossouw, acting director of NIH’s Women’s Health Initiative, which sponsored the study. The eight-year federal study of women between 50 and 79 was halted three years early because of the risks.

Contrary to once-popular belief, the pills can actually harm the hearts of previously healthy women, the study of 16,600 women concluded.

Doctors have known for some time that hormone replacement therapy (HRT) raised the risk of breast cancer and blood clots. Other possible side effects of HRT include stroke, high blood pressure, gallbladder cancer and depression.

“We’ve been telling women these things for years,” said Marcia Jones, who educates women nationwide from the Marietta-based Dixie PMS & Menopause Center (www.tidesoflife.com). She helped Marietta author Raquel Martin write “The Estrogen Alternative: Natural Hormone Therapy with Botanical Progesterone,” now in its third edition.

“Years ago, one out of 30 women developed breast cancer,” Mrs. Martin said. “Since the widespread use of Premarin (estrogen), Provera (synthetic progesterone), Prempro (a Premarin-Provera combination) and others, the numbers have increased to one out of seven.”

Researchers had been studying whether Prempro not only relieves the hot flashes, night sweats and vaginal dryness that can disrupt women’s lives at menopause, but also improves their health in the long run. It does not, the investigators concluded. In fact, research over the past decade has repeatedly dashed scientists’ hopes that HRT would help prevent heart disease, stroke, cancer and dementia.

“This is not a magic pill for women’s health,” said Dr. Nieca Goldberg, chief of the women’s heart program at Lenox Hill Hospital in New York. “The combined therapy carries more risks than benefits.”

On the good side, the Prempro did prevent hip fractures from osteoporosis and lowered the risk of colon cancer. But there are safer alternatives.

Plant-based estrogens have not been tested as thoroughly as Prempro, which is made in part with hormones from horses, but are just as effective, said Dr. Andrew Good, a gynecologist at the Mayo Clinic in Rochester.

“It hasn’t been clinically tested, but a lot of women report success with increasing their dietary soy intake,” Ms. Goldberg said.

Mrs. Martin recommends progesterones made from soy and wild yam. “Natural progesterone is the one that helps the heart — it’s anti-spasmodic,” she said. “Progestins [synthetics] can be lethal for some women: They actually cause vascular spasms and heart attacks.”

“It’s scary to me that someone wouldn’t look into natural alternatives before taking something so risky,” said Lisa Adams, sales manager for east Cobb manufacturer Pure Health International. Her company’s Pure-gesterone is one of several brands of soy- and yam-based progesterone cream sold in health food stores. “Why wouldn’t a doctor, if they’re truly interested in your welfare and safety, recommend something safe?”

Last week’s warnings don’t apply to the 8 million American women who use estrogen alone — a therapy restricted to those who’ve had hysterectomies, because estrogen can cause uterine cancer unless balanced by progestin or progesterone. The NIH is letting a study of those women continue, saying the risks and benefits remain unclear.

Also, the canceled study tested only Wyeth’s Prempro, the leading estrogen-progestin combination — not other brands that bear lower doses of estrogen or estrogen skin patches.

“Wyeth’s product was different from ours,” said Gabrielle Andres of Marietta-based Solvay Pharmaceuticals, considered No. 2 in the U.S. market for hormone replacement therapy. “Ours is a micronized progesterone product, chemically identical to what is in a woman’s body.”

Rossouw said drug industry marketing to patients and doctors still intimates that hormones are great for overall health. “We hope that truth will win out over advertising.”

— Wire reports contributed to this story.