Last week, we received several questions about irregular periods:

• Isn't it normal for the first year of periods to be irregular?
• My daughter got her first period at 12, then didn't get another period for 4 months.  Is that ok?
• My daughter’s periods are completely unpredictable.  When should I worry?

Irregular periods may seem like the norm for young girls, but there’s a predictable pattern that the vast majority of girls will follow during the first few years of periods. By keeping track of her periods on a calendar, you and your daughter will be able to recognize what’s normal and what’s not.

To calculate cycle length (which is important) remember to count the number of days...