How long is a menstrual cycle?
For menstruating women, an average menstrual cycle lasts 28 days – starting with the first day of the last period (which, on average, lasts six days, with some women having a very light flow and others having a very heavy flow) and ending with the first day of the next menstrual period. However, the length of women’s cycles varies, particularly for the first one to two years after menarche (a young woman’s first menstrual period). Women may have cycles as short as 23 days, or as long as 35 days. However, anything that deviates from this range is considered abnormal and may require medical attention.
