The most common cause of amenorrhea is pregnancy. It is important to determine if you are pregnant in order to get early care.
Other causes may be related to hormones. The hormones in our bodies control the menstrual cycle. If there is an abnormality with the release of the hormones or the body's ability to correctly use or make those hormones, a problem with the menstrual cycle results.
Sometimes, the absence of reproductive organs (uterus, cervix or vagina) may be the cause of amenorrhea.
In some cases, increased activity, medications or stress may alter the body's ability to release appropriate hormones to have menses. It is something that can be determined by your healthcare provider.