Most women can plan their social calendar around their period. But sometimes your flow may not be regular and can disappear for days at a time.

This can get especially worrying if you haven't been trying to have a baby or haven't been sexually active.

There are many other reasons why your period could disappear for longer than called for.

Here are 6 of them:

1. Strenuous exercise

When you over-exert your body in terms of diet or due to a rigorous training regimen, you could find your period disappearing.

2. Stress

This happens when the part of your brain that controls your period is affected by stress. This is known as hypothalamic amenorrhea.

3. PCOS

Polycystic Ovary Symtpom is a hormonal imbalance brought about by lack of ovulation. It can often lead to irregular periods, and can cause excessive hair growth, obesity and acne.

4. Chronic illness

An illness left unchecked can cause irregularities in a woman's system which can lead to irregular periods.

5. Premature menopause

Also known as premature ovarian failure, this is triggered by irregular hormones and is experienced by women under 40.

6. Birth Control

Some pills can cause your period to skip. This happens because they cause ovulation to stop.