LMP, or Last Menstrual Period, refers to the first day of a woman's most recent menstrual cycle. It is an important date used in various medical contexts, including estimating pregnancy due dates and assessing menstrual health. The menstrual cycle typically lasts about 28 days, but it can vary from 21 to 35 days among individuals. During menstruation, the body sheds the lining of the uterus, resulting in bleeding that usually lasts between 3 to 7 days. This process is a natural part of the reproductive cycle and is regulated by hormones such as estrogen and progesterone. Understanding LMP helps healthcare providers monitor reproductive health effectively.