Women's Health Initiative trial halted (2002)
A landmark US government-funded trial was stopped early when combined estrogen-progestin therapy showed increased risks of breast cancer, heart attack, stroke and blood clots. Hormone therapy prescriptions in the United States plummeted in the years that followed.
Doctors stopped prescribing HRT broadly and millions of women stopped taking it.
Two decades of caution followed, with later analysis finding risks depended heavily on a woman's age when she started therapy.
The new ACOG guideline directly confronts this legacy, declaring hormone therapy safety 'well-established' when started within 10 years of menopause or before age 60.
