What are irregular periods

Your menstrual cycle begins on the first day of your menstruation and continues up to, but not including, the first day of your next period. Women’s cycles range from 21-40 days or more, with an average of around 28 days. The length of your cycle may change from month to month. Periods usually last between two to seven days and blood loss varies from light to heavy and bright red to dark brown.

Your periods are considered irregular if your menstrual cycle is shorter or longer than average. This means that the time from the first day of your last period up to the start of your next period is less than 24 days or more than 38 days.

Your periods can also be irregular if your cycle length varies by more than 20 days from month to month ¹. An example would be your cycle jumping from a normal 25-day cycle to a 46-day cycle the next month and then back to a 25-day cycle the following month.

Irregular periods are normal for teenage girls and perimenopausal women. Teen girls’ periods may be irregular for the first few years of getting her period before becoming more regular. During the transition to menopause, called perimenopause, menstrual cycles may become more irregular over time.

Even though girls get their periods on a cycle, that cycle can take different amounts of time each month. For example, a girl might get her period after 24 days one month and after 42 days the next. These are called irregular periods.

Any alteration in what you consider to be your normal cycle can be a cause for concern. Variations may mean you have a period more often or less often than is normal for you or you may not have a period at all. You may also bleed more or less than normal, and the length of your period may also change.

The absence of periods (or amenorrhoea) usually occurs because an egg is not produced in the ovaries. The most common causes of absent periods are:

• not having started puberty
• pregnancy
• breastfeeding
• menopause.

There are several other factors that may cause your periods to stop or to become lighter or less frequent, such as:

• excessive exercise
• being underweight or excessive dieting
• feeling upset or stressed
• severe long term illness
• a hormonal imbalance
• a thyroid disorder
• stopping or starting the contraceptive pill or other hormonal contraception (including the patch, IUD (Mirena) coil, implant (rods) or injection)
• some medicines
• disorders of the womb or ovaries.

Experiencing changes in the frequency or duration of periods is common in most women at some point in their lives. Any treatment or investigation of irregular or light periods will depend on the likely cause. There may, for example, be no need for treatment if you are nearing the menopause as irregular periods are common during this time.

What are regular periods?

Most girls get their first period between the ages of 10 and 15, but some get it earlier and some later. The first period is known as menarche (pronounced: MEN-ar-kee).

A girl’s monthly cycle is the number of days from the start of her period to the start of the next time she gets her period. You often hear this is a 28-day cycle. But 28 is just an average figure that doctors use. Cycle lengths vary — some are 24 days, some are 34 days. And a girl may notice that her cycles are different lengths each month — especially for the few years after she first starts getting her period.

Early in a girl’s cycle, her ovaries start preparing one egg. At the same time, the lining of the uterus becomes thick to prepare a nesting place for a fertilized egg in the event that the girl becomes pregnant.

About 2 weeks before a girl gets her period, the egg is released from the ovary (this is called ovulation). The egg travels through the fallopian tube into the uterus. If the egg isn’t fertilized by sperm, it starts to fall apart. Then the lining and egg leave a girl’s body as her period and the whole thing starts all over again — that’s why we use the word “cycle.” The first day a girl’s period comes is Day 1 of her cycle.

A girl’s body may not follow an exact schedule. It’s common, especially in the first 2 years after a girl starts getting her period, to skip periods or to have irregular periods. Illness, rapid weight change, or stress can also make things more unpredictable. That’s because the part of the brain that regulates periods is influenced by events like these. Going on a trip or having a major change in schedule can also make your period come at a different time than expected. All of this is perfectly normal.

It’s also normal for the number of days a girl has her period to vary. Sometimes a girl may bleed for 2 days, sometimes it may last a week. That’s because the level of hormones the body makes can be different from one cycle to the next, and this affects the amount and length of bleeding.

If my period is irregular, how do I know when I will get it?

If your cycle is not regular, you’ll want to pay attention to the clues your body may give you that your period is coming soon. These may include:

• back cramps or stiffness
• heavier breasts or breast soreness
• headaches
• acne breakouts
• disturbed sleep patterns
• mood swings
• bloating
• loose stools

Keep some pads or tampons in your backpack or purse, just so you’ll have them handy in case your period comes when you’re not expecting it. You may even want to carry an extra pair of underwear.

Should I worry about irregular periods?

Talk to your doctor if you have had sex and have missed a period because you could be pregnant. Also let the doctor know if:

• You were having regular periods that then become irregular.
• You stop getting your period.
• You have extra hair growth on the face, chin, chest, or abdomen.
• You start having periods that last longer than 7 days, are heavy, or are coming more often than every 21 days.
• Your period comes less often than every 45 days.
• You have severe cramping or abdominal pain.
• You have bleeding in between your periods.
• Your periods are irregular for 3 years or more.

The doctor may prescribe hormone pills or other medicines, or recommend lifestyle changes that can help you to have regular periods.

Causes of irregular periods

Causes of irregular periods include:

• Eating disorders. Irregular or missed periods can be signs of eating disorders, most often anorexia nervosa. But any eating disorder, including bulimia nervosa and binge eating disorder, can cause irregular periods.
• Thyroid problems, such as hyperthyroidism (overactive thyroid). Hyperthyroidism, or overactive thyroid, causes your thyroid to make more thyroid hormone than your body needs. Hyperthyroidism can also cause fewer and lighter menstrual periods than normal.
• High amounts of prolactin in your blood. This condition is called hyperprolactinemia. Prolactin is the hormone that causes breasts to grow during puberty and makes breastmilk after childbirth. It also helps control the menstrual cycle.
• Certain medicines, such as those for epilepsy or anxiety
• Polycystic ovary syndrome (PCOS), a condition that usually causes multiple ovarian cysts, hormonal imbalance, and irregular periods. About 1 in 10 women with irregular menstrual cycles has PCOS ².
• Primary ovarian insufficiency. Primary ovarian insufficiency happens when your ovaries stop working normally before age 40. It can happen as early as the teenage years. Primary ovarian insufficiency is not the same as premature menopause. Unlike women who go through premature menopause, women with primary ovarian insufficiency may still have periods, though they are most often irregular. Women with primary ovarian insufficiency may also still get pregnant.
• Pelvic inflammatory disease (PID). Irregular periods can be a sign of pelvic inflammatory disease (PID), an infection of the reproductive organs. Pelvic inflammatory disease (PID) is most often caused by a sexually transmitted infection (STI).
• Stress. Studies show high levels of chronic (long-term) stress can lead to irregular periods ³.
• Uncontrolled diabetes. Type 1 and type 2 diabetes can cause irregular periods, but getting your diabetes under control can help your periods become more regular ⁴.
• Obesity. The extra fat in the body makes the hormone estrogen. The extra estrogen changes the normal menstrual cycle and can cause missed, irregular, or heavy periods.

Most of the time, irregular periods are part of the normal changes that can happen when you’re a teen. As you get older, your cycle will probably settle into a recognizable pattern.

Sometimes, irregular periods can be caused by some medicines, exercising too much, having a very low or high body weight, or not eating enough calories.

Hormone imbalances can also cause irregular periods. For example, thyroid hormone levels that are too low or too high can cause problems with periods. Some girls have extra androgen, a hormone that can cause hair growth on the face, chin, chest, and abdomen. Extra androgen can also makes girls gain weight and have irregular periods.

Girls who are pregnant also will not get their periods.

Irregular periods treatment

Treatment depends on the cause of your irregular periods. Your doctor may give you hormonal birth control, such as a hormonal IUD ⁵, the pill, shot, or vaginal ring ⁶, to help control your menstrual cycle. Hormonal birth control is sometimes prescribed by doctors for women’s health concerns other than preventing pregnancy.

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