When can progesterone be added in the treatment of estradiol for women with an intact uterus?

Adding progesterone in the treatment of estradiol for women with an intact uterus is necessary for the prevention of endometrial hyperplasia, which can occur with unopposed estrogen therapy. The correct approach is to administer progesterone for a specified number of days each month, typically around 12 to 14 days. This regimen allows for adequate endometrial protection while still providing the benefits of estrogen therapy for menopausal symptoms.

This cyclical use of progesterone helps to induce a withdrawal bleed, similar to a menstrual cycle, ensuring the endometrial lining does not become overly thickened. When progesterone is administered in this manner, it balances the effects of estrogen, which is critical for women who have not undergone a hysterectomy.

Other scenarios, such as adding progesterone only when hot flashes occur or when estrogen levels are high, do not provide a structured or sufficient approach to protect the endometrial lining. Similarly, continuous use of progesterone is generally considered less common, as it may lead to side effects like breakthrough bleeding and may not be necessary for all women depending on their individual circumstances and response to treatment.