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How does Femara affect your period?

Medically reviewed by Melisa Puckey, BPharm. Last updated on July 4, 2022.

Official answer


How does Femara affect your period?

  • When Femara is used for breast cancer treatment it is only for women who are postmenopausal, and therefore they should not be having periods. However Femara can cause vaginal bleeding in approximately 13% for patients on Femara.
  • Femara is also taken ‘off-label’ for women who are at the menstruating stage of life, to induce the eggs being released from the ovaries (ovulation) in women who have ovulation problems, polycystic ovary syndrome and unexplained fertility.
  • Women who are having difficulty conceiving take Femara to induce ovulation in hopes to become pregnant and if successful this would result in no period. If this does not result in pregnancy you would expect to get your period approximately 14 days after you ovulate which may be day 28 of your cycle.

When do you take Femara to induce ovulation?

Femara is taken once a day for 5 days, starting on day 3 of your period and continuing to day 7. If you are not having periods naturally you may be given progestin to induce your period, then you can start Femara once you have your period. After taking the 5 day course of Femara you should ovulate between day 11 and day 14 which is when intrauterine insemination takes place or when you should have intercourse.

How does Femara induce ovulation?

Femara lowers your estrogen levels, which causes an increase in two hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH). The increase in these two hormones stimulate the egg to mature and be released from your ovaries.

Bottom Line:

  • Women who are taking Femara for breast cancer should be postmenopausal, so should not be having periods, but may have some vaginal bleeding as a side effect from Femara.
  • When Femara is being taken to induce ovulation it should be taken once daily on day 3 to day 7 of your cycle.
  • If you do not become pregnant you will get your period usually 14 days after your induced ovulation, which is approximately day 28 of your menstrual cycle.

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