Well, there are some factors that can prevent a girl from getting her period, or cause it to be delayed. The obvious reasons are if she is pregnant, or on Birth Control. Otherwise, some factors could be sudden weight gain or loss, because it chnages the hormone levels in the body very rapidly. Some medications might cause a missed period. Stress can also result in a missed period or two. If a girl doesn't have her period for mor than thee months in a row, she should go to the doctor because that could be a sign of a more serious medical condition.
See the related link on what causes brown discharge after period.
Any number of causes. Food and the start of a period.
pregnancy
Period comes when you drink Malta . It causes miscarriage.
The causes of coming your periods twice a week are because, either you are a new starter to your period, in other words, your period is new, or, you ovulated 2 eggs which happens rarely.
If you are bleeding and it's not your period, it is important that you see a medical professional. There are many causes for bleeding and not being on a period. Certain causes may be extreme stress, a side-effect of birth control, or even pregnancy.
illness
Your period..............maybe or skid marks
The hormones that rise and fall.
Pregnancy.
they are moody and nasty
A month is a somewhat arbitrary period of time that loosely approximates the period of one lunar cycle.