If you've started having your menstrual cycle, I’m sure you've noticed that your periods don’t always arrive with clockwork precision. Sometimes they’re early, others are late and some are even interrupted. At other times, they don’t last the same number of days every month. Are you worried about the irregularity? Don’t fret. In most cases, it’s due to a normal adjustment in your body, but you should be alert for other signs that might mean that you should seek medical attention.

The human body is a wonderful arrangement of organs and functions, but don’t expect it to work with the precision of a machine, much less a Swiss watch! Your menstrual cycle is no exception. From your first period (or menarche), your body goes through a series of adjustments that can last for two (sometimes three) years. During this time it’s perfectly normal to experience irregularities in your periods. Some may be shorter, some longer, some more intense than others and you may even skip a month. Why is that? It’s because the hormonal levels that regulate the frequency and intensity of your period may vary from month to month. In addition, irregularities may occur (or intensify) if you get sick, if you gain weight quickly or if you go through stressful situations at home or school.

A calendar is a simple and easy-to-use tool that can help a lot during this time. Start out by writing down the day your period starts every month so you can determine your normal menstrual cycle. This is calculated by counting the number of days from the start of one period to the start of the next. In theory, as we menstruate once a month, the cycle should be 28 days long. But this is only an average to use as a guide. Cycles vary for most women – periods can arrive every 28, 30, 31 days or even farther apart. The important thing is their frequency. After a few months of writing them down, you will discover your own pattern or rhythm. But, even if you're experiencing some irregularities, your own body will let you know that it’s nearly time for your next period. Here are some of the signs:

• Swelling in your breasts and belly
• Headache
• Pain and/or discomfort in your lower back
• Changes in your mood - Sadness or feeling irritable for no apparent reason
• Acne breakouts

Other teenagers like you may experience irregular periods, or even stop having them completely, for reasons like taking certain medications, consuming too few calories, or having a body weight that is too low. Some girls may have problems with their thyroid gland, or their bodies may produce too much androgen. (Androgen is a male hormone, which results in the growth of hair on the face, chest or abdomen. It can also cause excess weight gain). In these cases, or if the irregularities persist for more than three years, you should seek medical assistance.

You should also visit your doctor:

• If suddenly your periods last more than a week
• If the bleeding seems intense and you have severe abdominal pain
• If your period occurs in less than 21 days, or you get it twice a month
• If your period is more than 45 days late

You’re living through a very important stage in your life, in which your body is going through intense changes, such as starting your menstrual cycle. But remember it’s a normal process, part of becoming sexually mature. And the more you know about this process, the more confident and secure you will feel even, when there is an irregularity in your periods. Over time, everything will come into balance. Meanwhile, if you notice anything that worries you or if you have any questions, ask your family doctor or gynecologist.