Women cannot get pregnant once they have experienced menopause, which is complete after menstrual periods have stopped for a year, according to the National Institute on Aging. The chances of a woman in perimenopause getting pregnant in any given cycle is 5 percent, notes Healthline.
Menopause in women is preceded by perimenopause, according to the National Institute on Aging. Perimenopause causes fluctuating hormones and more frequent anovulatory cycles. Women are not fertile during anovulatory cycles, explains Healthline. Further, eggs that women produce during perimenopause are low quality, which makes conception difficult for women over age 40. Despite these obstacles, it is still possible for a women to get pregnant until menopause is complete, and thus perimenopausal women who do not wish to get pregnant should use birth control.