Ideal menstruation occurs on a regular schedule, with cycles beginning on average 28 days after the start of the previous period. This is not true for everyone, but you can determine your definition of what a typical cycle looks like based on patterns seen in period tracking. When your monthly visitor hasn't made its scheduled appearance, it's easy to panic, but the delay is not necessarily a cause for concern.
Let's discuss some reasons your period might be late.
The most obvious cause for a late period is pregnancy. Because shedding of the uterine lining—some of what is seen as discharge during a period—does not occur if a fertilized zygote or egg has been implanted, a missed period is often the first indicator of pregnancy. Even with precautions and conventional birth control, it is still possible to get pregnant. If you're late, see a doctor or take a home pregnancy test.