According to WebMD, after a full year of not having monthly periods due to menopause, a woman can no longer become pregnant. A woman can become pregnant when experiencing the early stages of menopause.
During the first stages of menopause a woman may start missing some of her menstrual cycles in addition to the other hormonal changes that occur. During this time, there is still a slight possibility that the woman can become pregnant. For this reason, birth control should still be used until the woman's cycles stop and her physician confirms that she is postmenopausal. According to the Office on Women's Health, if a woman experiences several missed periods and later begins spotting, she should be checked to rule out gynecological cancer.