What Are Irregular Periods?

Menstrual cycles don’t always run like clockwork. While some women get their periods right on schedule every 28 days, other women are left guessing. Some might skip a month altogether; others might vary from cycle to cycle. But having irregular periods on a frequent basis can have different effects on your body.

Who Has Irregular Periods?

When Is a Menstrual Period Considered Irregular?

A normal cycle from the first day of one period to the first day of the next can be anywhere from 21 to 35 days, says Becky Lynn, MD, the CEO and founder of Evora Women’s Health in Creve Coeur, Missouri. “We all think that 28 days is the normal cycle, but there’s actually some room for variability,” she adds.

Medical Conditions Can Disrupt Menstrual Cycles

Many variables can affect the length and timing of your menstrual cycle. Some are correctable, but others can signal significant medical issues.

• Polyendocrine Metabolic Ovarian Syndrome (PMOS) Formerly known as polycystic ovary syndrome (PCOS), this metabolic and hormonal disorder occurs when the ovaries or adrenal glands overproduce the male hormones (androgens) and the body has insulin resistance.

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   PMOS is a common cause of heavy or extended bleeding.

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• Thyroid or Pituitary Disorders Hypothyroidism (when your thyroid gland doesn’t produce enough thyroid hormone), hyperthyroidism (your gland produces too much), and hyperprolactinemia (you have too much prolactin, a hormone from your pituitary gland, in your blood) can all affect menstrual regularity, says Dr. Lynn. One study reported that nearly 14 percent of adult women are affected by thyroid disorders.

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• Pelvic Inflammatory Disease (PID) An inflammation of the female reproductive system, PID is usually caused by sexually transmitted infections.

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Non-Disease-Related Issues Can Cause Irregular Periods

Lynn says that irregular menstrual cycles can also be caused by:

• Perimenopause As you transition to menopause, which can last as long as 10 years, your menstrual cycles will become erratic as part of the process. If you skip more than two periods, you are probably in late perimenopause.

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   Some research has estimated that 82 percent of premenopausal women experience irregular menstruation in the approach to menopause.

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• Stress and Anxiety Chronic stress or even short-term anxiety about a specific problem can wreak havoc with your hormone balance, causing a missed or irregular period.
• Extreme Exercise Exercising too much can throw off the timing of menstrual bleeding and sometimes stop it.
• Eating Disorders, Extreme Dieting, or Weight Loss Being underweight, whether from extreme exercise, dieting, an eating disorder, or illness, can have the same effect.
• Age As mentioned, perimenopause and menopause have a major effect. But being young can create irregularities as well. “Once menstruation begins in young women, it can take several years before it falls into a pattern,” says Lynn.
• Birth Control Contraception, including birth control pills, IUDs, implants, and rings can also cause irregular bleeding.
• Smoking and Vaping The smoking or vaping of marijuana, cigarettes, or nicotine-containing products can affect menstrual cycles, according to research.

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Irregular Periods May Occur While Breastfeeding a Newborn

Sometimes called “nature’s birth control,” exclusive breastfeeding may cause amenorrhea — no menstruation at all — because you are less likely to ovulate for up to about six months. (Learn more before you use this method for birth control — many experts recommend new moms pair this approach with an additional birth control method, such as condoms, to increase effectiveness.)

Irregular Periods May Occur After Miscarriage, Pregnancy Loss

When to See a Doctor

A couple of irregular periods per year are usually nothing to worry about. Any more than that, and you should see a doctor to be sure an ovulation problem or health condition isn’t the cause. “If you are someone who’s not on contraceptives and not of age for perimenopause or menopause and your periods are irregular, you should alert your physician,” says Lynn. If you do have PMOS, an irregular cycle can increase your risk of uterine cancer, Lynn adds.

Sometimes, a period is late for a very good reason. Before you schedule an appointment with your doctor, you might want to rule out pregnancy.

Treatment Options

If stress is a possible culprit in your irregular cycle, try stress-management techniques, such as meditation, yoga, tai chi, visualization, cognitive behavioral therapy, or biofeedback. Avoid over-exercising, and try not to diet excessively. If you need help figuring out what eating plan is best for you, contact a registered dietitian. For all medical issues, consult your healthcare professional.

Can You Get Pregnant With an Irregular Period?

Absolutely yes, says Lynn. “Sometimes you can ovulate with irregular cycles, sometimes you don’t ovulate with irregular cycles,” she says. “If you’re not ovulating, you’re not going to get pregnant, but if you are ovulating with irregular cycles, you can. You can have bleeding without ovulating, but it’s a real period only if you ovulate. You should use contraception if not desiring pregnancy and to protect against STDs.”

Understanding Ovulation

If you are interested in ovulation timing for family planning or any reason, but you have irregular periods, see your doctor first. If you do have PMOS or another condition, you can get treated as soon as possible.

Ovulation calculators are not very helpful for women with irregular menstruation. Just as you can’t assume you are not ovulating if you have PMOS, you also can’t assume that you are. That’s another reason to get checked out by your doctor soon, so you can begin treatment before your fertility window closes.

Although none of these fertility awareness methods (FAM) is foolproof, women with regular or mildly irregular periods may be able to help predict ovulation by tracking their cycles and monitoring themselves for ovulation symptoms, such as changes in cervical mucus or basal body temperature.

Learn more about interpreting your body’s ovulation symptoms from a reputable resource, such as the American Pregnancy Association or Planned Parenthood. Products such as apps, testing kits, and ovulation monitors may help some women figure out when they are ovulating, but not all of these are accurate, so it’s best to talk to your doctor before investing time and money in these products.