Estriol

Key facts

• Estriol is a naturally occurring, low-potency estrogen. Applied inside the vagina, it restores moisture and thickness to tissue that has thinned after menopause.
• It comes as a cream, pessary or vaginal tablet, usually used daily for the first two to three weeks and then reduced to two or three times a week.
• Any unexplained vaginal bleeding must be checked by a doctor before starting estriol and reported immediately if it happens during treatment, since it can be a sign of cancer of the womb lining.
• Seek urgent care for heavy vaginal bleeding, signs of a blood clot (leg swelling or pain, sudden breathlessness), or a new breast lump.

What estriol treats

Estriol treats the vaginal and urinary symptoms of the genitourinary syndrome of menopause: dryness, burning, itching, pain during sex, and recurrent urinary urgency or discomfort caused by falling estrogen levels. It works on the vaginal and lower urinary tract tissue directly and is not intended to relieve hot flushes or other whole-body menopause symptoms.

How estriol works

After menopause, low estrogen causes the lining of the vagina and lower urinary tract to thin, dry out and become fragile. Estriol binds to estrogen receptors in this tissue, prompting the cells to thicken, rebuild their blood supply, and produce more natural lubrication. Because it is a short-acting, low-potency estrogen applied locally, only a small amount reaches the rest of the body.

Before you take it

• Do not use estriol if you have had breast cancer or another estrogen-sensitive cancer, unexplained vaginal bleeding, a previous blood clot in the legs or lungs, or active liver disease.
• Estriol is contraindicated in pregnancy and should be stopped at once if pregnancy occurs.
• Tell your doctor about migraine, diabetes, gallbladder disease, or a family history of blood clots, since these need individual assessment.
• Using estriol together with other hormone treatments should only happen under medical supervision, since the effects add up.

Side effects

Common effects include mild irritation at the application site, spotting, and breast tenderness, most of which settle within the first weeks.

Stop and seek urgent medical care for any of these:

• Heavy or persistent vaginal bleeding.
• Leg pain or swelling, chest pain, or sudden shortness of breath.
• A new breast lump or unusual nipple discharge.

Safety essentials

• Report any vaginal bleeding that starts after you begin estriol to your doctor promptly. It must be investigated to rule out cancer of the womb lining before treatment continues.
• Use the lowest dose that controls your symptoms for the shortest time needed, and have your doctor review whether you still need treatment at least once a year.
• Do not use estriol if you are or might be pregnant.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.