As long as a woman's short menstrual period is part of a steady pattern and fits within this range, this is normal menstruation for her body. If your period lasts for three days, month in and month out, that's your pattern, says Maria Arias, MD, a gynecologist at Atlanta Women's Specialists in Georgia.Reasons for a Short Menstrual Period. Estrogen is the all-important hormone required to create the endometrium each month.f your period lasts for three days, month in and month out, that's your pattern, says Maria Arias, MD, a gynecologist at Atlanta Women's Specialists in Georgia. Reasons for a Short Menstrual Period. Estrogen is the all-important hormone required to create the endometrium each month.