Irregular menstruation can occur at the beginning of puberty in girls, and it is often not a cause for concern, as irregularity occurs as a result of the following:

• Natural hormone change in puberty, it is normal for the body to go through a number of changes, these changes lead to a change in hormones, which can take some time to stabilize and balance and once a balance of these hormones occurs, the menstrual cycle will be regular.
• Exercising intensely.
• Not eating healthy food and not getting enough calories that the body needs.
• Not getting an appropriate weight, and therefore being thin or obese can lead to irregular menstruation.
• Take some types of medications, especially steroids.

In some cases, irregular periods may be due to a health problem such as thyroid disease, polycystic ovary syndrome, eating disorders, endometriosis and other diseases that may cause irregular periods.