What changes occur in the menstrual cycle during the menopause transition?

During the menopause transition, one of the hallmark changes observed in the menstrual cycle is that menstrual periods become fewer and further apart. This is indicative of the decline in ovarian function and the fluctuating levels of estrogen and progesterone. As a woman approaches menopause, the ovaries gradually produce fewer hormones, which leads to irregularities in the menstrual cycle.

Initially, periods may become more irregular, with some cycles being shorter and others longer, but over time, the overall trend is a reduction in the frequency of menstruation. This progression can result in significant spacing between menstrual periods, often leading to fewer cycles per year and eventually culminating in the cessation of menstruation altogether, known as menopause.

In contrast, while changes in the luteal phase and follicular phase may occur during this transition, the most notable and consistent observation for many women is the frequency of menstrual periods decreasing. The other changes like a shortening or lengthening of different phases can vary significantly among individuals and are not as universally observed as the overall trend described in the correct answer.