Not necessarily. Whether or not chemotherapy will send you into menopause depends on several things — mostly upon your age, but also your state of health, the location and staging of the cancer, and the type and dosage of chemotherapy you are receiving. If your body is not close to menopause prior to starting chemotherapy, your periods may return and you may regain normal ovarian function, provided therapy hasn’t overly disturbed your ovaries or your endocrine hormone profile.
Because the ovaries can sometimes be damaged by chemotherapy, they may become unable to produce their usual hormones. A drastic drop in estrogen or changes in overall hormone levels can provoke menopausal symptoms. After chemotherapy, it may take months or years for your ovaries to recover normal function.
The closer you are to a menopausal age, the more likely it is that you will notice menopausal symptoms during chemotherapy, and the more likely it is that your menopause will be permanent. This is called chemo-induced menopause. Research shows that chemotherapy–induced menopause occurs in 10–50% of women under the age of 40 and in 50–94% of women over the age of 40. But again, these are statistics, and there is certainly wide variation in the effects of chemotherapy on the female endocrine system.