The menstrual cycle repeats approximately every 28 days, and includes a variety of body changes that are mediated by hormones in a woman's body. The purpose of the cycle is to prepare the uterus for implantation of a fertilized egg, should conception occur during the appropriate window. Because of the many hormones involved in producing the changes of the menstrual cycle, there are a number of symptoms associated with an oncoming period. Many of these can be surprisingly cold- or flu-like in nature.
Headaches
One of the most common flu-like symptoms of an approaching period is headache. Whereas most women experience dull, mild aching, some have migraines. The National Headache Foundation explains that this symptom is due to high levels of estrogen and progesterone in a woman's body in the days leading up to her menstrual periods. For most women, headaches are worst during the week just before a menstrual period. This is also the period of time in a woman's cycle during which levels of the hormones estrogen and progesterone are highest. The National Headache Foundation further notes that women taking birth control pills are particularly susceptible to pre-period headaches due to the hormones in the pills.
Fatigue
The National Institute of Child Health and Human Development notes that it's not uncommon for women to feel fatigue or muscle soreness in the days leading up to a menstrual period. These symptoms also commonly occur with colds or the flu, but for different reasons. Colds and other viruses trigger immune symptom responses, leading to development of a fever and aching joints because the immune cells release irritating chemicals that help fight infection, with some unpleasant side effects. Before a menstrual period, explains the National Headache Foundation, fatigue and soreness are the result of high levels of hormones as opposed to the action of the immune system. Generally, these symptoms resolve as the period begins.
Muscle Cramps
KnowMyCycle.com, a website that provides information about menstrual cycles to teenage girls and young women, notes that cramping frequently occurs before menstrual periods. The cramping can feel very flu-like, particularly if it occurs in the lower back, since colds and flu frequently cause low back pain. Women can get some relief from this cramping and low back pain with the help of a heating pad, or an ice pack, if cold feels better than heat. Massage also helps in some cases. As with other premenstrual symptoms, back pain and cramping generally dissipate by the first or second day of the menstrual period.
