Many women experience shorter periods as they enter menopause, according to the American Society for Reproductive Medicine. The period of perimenopause is characterized by menstrual irregularities as levels of reproductive hormones fluctuate, and women with shorter periods are likely experiencing a greater drop in these hormones.
The reason why many women experience menstrual irregularities as they go through perimenopause is that the levels of estrogen, progesterone and follicle stimulating hormone begin to vary and drop overall, states the American Society for Reproductive Medicine. As these hormone levels drop, the ovaries shrink and release eggs less frequently. The uterine lining does not build up nor does it need to be shed as often, resulting in shorter and lighter periods.
Fluctuations in estrogen, progesterone and FSH can have different effects on different women, as stated on MedicineNet.com. Some women experience heavier, more frequent periods during menopause. Each woman's experience and symptoms are unique.