# Who should not have bioidentical hormone therapy? > Why the timing of hormone therapy matters — the window of opportunity — and the situations in which bioidentical hormone therapy is not given at all. Published: 24 June 2026 · Medically reviewed by: Op. Dr. Murat Alpay **Why the timing of hormone therapy matters — the window of opportunity — and the situations in which bioidentical hormone therapy is not given at all.** **Short answer:** Bioidentical hormone therapy is not used in women with a history of oestrogen-sensitive breast or womb-lining cancer, a blood clot in the leg or lungs, a recent heart attack or stroke, or vaginal bleeding without a known cause. Starting treatment within 10 years of the menopause or before 60 (the window of opportunity) matters; starting it for the first time more than 10 years after the menopause or after 60 is generally not recommended. Bioidentical hormone therapy replaces the oestrogen and progesterone that fall away during the menopause, and it is an effective way of managing the complaints that reduce quality of life: hot flushes, disturbed sleep, bone loss. But how well it works — and its favourable effect on heart and vascular health — depends to a great extent on **when** it is started. Medicine calls this the **window of opportunity**. For the overall framework of the treatment, see our [bioidentical hormone therapy](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) page. ## What is the window of opportunity? According to the guidelines, starting hormone therapy **within the first 10 years after the menopause, or between the ages of 50 and 60**, is described as the window of opportunity. Starting within this critical period gives the greatest benefit in protecting against cardiovascular disease and preventing bone loss, while keeping the possible risks as low as they can be. In women who are more than 10 years past the menopause or over the age of 60, starting this treatment *for the first time* is generally not recommended, because it can increase the risk of heart disease and stroke. That is why it matters so much to see a gynaecologist without delay once menopausal symptoms begin — so that the window is not missed. Related treatment page [Body-Identical Hormone Therapy](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) Body-identical hormones are hormones with a chemical structure similar to those the ovaries produce. [Details →](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) ## When is [bioidentical hormone therapy](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) not given at all? Even when the timing is right, there are situations in which this treatment should not be used: - **A history of breast or womb cancer:** it is not given to women with a past or active oestrogen-sensitive cancer of the breast or of the lining of the womb (the endometrium). - **Clotting problems:** it cannot be used where there is an active or past deep vein thrombosis (a clot in the leg) or pulmonary embolism (a clot travelling to the lung). - **Previous heart attack or stroke:** the treatment is contraindicated in patients who have recently had an arterial event such as a heart attack or a stroke. - **Undiagnosed vaginal bleeding:** where bleeding has no medically established cause, treatment is not started until the underlying reason has been clarified. - **Severe liver disease:** it is not preferred in people with active liver disease, because the processing of hormones taken from outside is impaired. ## Why the assessment beforehand matters That bioidentical hormones match the body's own does not mean they can be used without medical supervision. Menopause treatment should be planned individually, on the basis of a smear test, mammography and detailed blood tests. Results of any medical procedure can vary from person to person. *This page is for information. It does not replace an examination or individual medical advice.* Written and reviewed by **Op. Dr. Murat Alpay** Specialist in Obstetrics and Gynaecology · Istanbul University, Istanbul Faculty of Medicine (Çapa) [Full biography →](https://www.muratalpay.com.tr/en/hakkinda/) [← All posts](https://www.muratalpay.com.tr/en/blog/) --- Original page: https://www.muratalpay.com.tr/en/blog/biyoesdeger-hormon-tedavisi-kimlere-uygulanmaz/ Last updated: 2026-10-08 Op. Dr. Murat Alpay — Specialist in Obstetrics and Gynaecology Op. Dr. Murat Alpay Practice, Tekelioğlu Cd. No:51 B Kat:2, Filo Apt., 07160 Muratpaşa / Antalya 0505 351 77 88 · Monday – Saturday 09:00 – 18:00 · Closed on Sunday *This information is for general guidance only and does not replace examination, diagnosis or treatment.*