Understanding perimenopause, menopause and hormone therapy

Hormone therapy has received increased attention as more women seek relief from the physical and mental changes associated with perimenopause and menopause. Understanding the basics of hormone therapy can empower women to make informed choices about their health during this transition. Hormone therapy is typically considered for women who are perimenopausal or menopausal and experiencing physical, emotional and sexual symptoms that disrupt quality of life.

Hormone therapy or hormone replacement therapy?

Hormone therapy is often referred to as “hormone replacement therapy,” but the term “replacement” can be misleading. The primary goal of hormone therapy is to alleviate symptoms resulting from perimenopause and menopause, not to restore hormone levels to those seen before menopause. Hormone therapy is:

• Designed to use the lowest effective dose of hormones to help steady hormonal fluctuations or decline and to improve symptoms.
• Not used to reverse aging or to return hormone levels to those seen before menopause.
• This approach helps set realistic expectations and supports individualized care.

How does hormone therapy work?

To better understand hormone therapy, it is helpful to know the differences between perimenopause and menopause, as well as the symptoms associated with each phase.

• Perimenopause is the transition before menopause, when women may notice physical and emotional changes.
  • Symptoms can begin about four to seven years before menopause.
  • During this time, hormone production can become erratic and unpredictable.
  • Periods may still be regular, but symptoms can develop, including changes in mood, sleep, energy, memory, sexual health and menstrual regularity.
• Menopause is defined as 12 consecutive months without a period in a woman with a uterus who is not using hormonal contraception and who has not had a procedure that alters the menstrual cycle, such as an endometrial ablation.
  • Anything that affects periods can make it harder to identify when menopause has occurred. Lab tests alone cannot reliably diagnose menopause and may be misleading.

Women may begin experiencing perimenopause symptoms as early as their late 30s. Before considering hormone therapy, it is important to rule out other medical conditions, such as thyroid disease, diabetes or anemia, which can cause similar symptoms.

What hormones are used for hormone therapy?

Estrogen and progesterone are the two hormones used in hormone therapy. They are produced by the ovaries in a regular cycle during the premenopausal years.

• Estradiol is one of the most commonly used forms of estrogen to treat perimenopausal and menopausal symptoms. It is chemically identical to the estrogen produced by the ovaries. Another form is conjugated equine estrogen (Premarin).
• Oral estrogens, including estradiol and Premarin, are available in pill form. These formulations can increase the risk of blood clots, though to a lesser extent than oral contraceptive pills.
• Transdermal estrogens, including patches, gels and sprays, are absorbed through the skin and do not increase baseline clotting risk or cholesterol levels.
• Vaginal estrogen is FDA‑approved to treat the genitourinary syndrome of menopause.

Who should avoid hormone therapy?

Systemic hormone therapy is not recommended for women with:

• active liver disease
• recent heart attack or stroke
• active blood clots
• estrogen‑sensitive cancers
• unexplained vaginal bleeding

Why did hormone therapy use decrease in the early 2000s?

The use of hormone therapy declined following the 2002 Women’s Health Initiative study that showed a small increase in breast cancer risk among women using estrogen (conjugated equine estrogen or Premarin) combined with progestins. The increase amounted to about one additional case per 1,000 women per year. Importantly, the study found no increased risk of death from breast cancer among women who used hormone therapy.

Subsequent analyses showed that women who took estrogen alone had fewer cases of breast cancer than those in the placebo group. The risks observed were lower than those associated with factors such as obesity or alcohol use. Many participants in the original study were older and not experiencing menopause symptoms, and the hormone formulations studied are less commonly used today.

Benefits of hormone therapy

Women who start hormone therapy within 10 years of menopause or before age 60 have shown reduced risks of heart disease, type 2 diabetes, fractures and death from any cause. Beyond symptom relief, hormone therapy can contribute meaningfully to overall quality of life.

In November 2025, the Food and Drug Administration removed the black box warning for estrogen and progestogens after reviewing updated evidence. The warning had been based on outdated or misinterpreted data. A warning remains regarding the increased risk of endometrial cancer when estrogen is used alone in women with a uterus.