Does PCOS Always Cause Irregular Periods?

Irregular periods are a classic symptom of PCOS, or polycystic ovary syndrome. Sometimes, periods even stop. That said, some people with PCOS still have regular periods. And it's also possible that any irregularities in your menstrual cycle could be due to something else entirely.

This article explores what defines irregular periods, when PCOS may be determined as the cause, and what can be done to get menstruation back on schedule.

Irregular periods and PCOS
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How Are Irregular Periods Defined?

Most people with PCOS have absent periods or oligoovulation. Oligoovulation is when ovulation occurs infrequently or irregularly. A person with oligoovulation may have irregular periods or a very long cycle of more than 50 days.

It is normal to ovulate or release a mature egg once a month, about halfway through your cycle. Most normal periods, on average, are between 28 and 32 days. Anything shorter than 21 days or longer than 35 days is considered to be irregular.

Oligoovulation can make it difficult to track your fertile days if you're trying to conceive.

Not everyone with PCOS experiences absent or irregular cycles. Some have a regular monthly cycle.

Others have periods that occur too frequently—they may happen several times a month or last for weeks at a time. Heavy bleeding can cause these people to become anemic or have low iron levels.

Causes of Irregular Periods

If you are a teenager and have only recently got your first period, or an older person approaching menopause, irregular cycles are very common because your hormones are fluctuating. If you lose a significant amount of weight or are under a lot of stress, your periods may be affected as well.

Medically speaking, hypothalamic amenorrhea, pregnancy, and other hormonal conditions can all cause irregular or absent periods. It’s even possible for a woman to be born with a structural abnormality that can prevent her from getting a period, such as not having a uterus or cervix.

PCOS is diagnosed when a woman has irregular periods in addition to signs of elevated androgens, either by her symptoms or through blood testing. Symptoms of high testosterone (one type of androgen) include abnormal hair growth, hair loss, and acne.

Treatment for Irregular Periods

There are many different ways to treat PCOS depending on your goals and health history. Some healthcare providers recommend oral contraceptives to balance out hormones and create a regular cycle.

Although not indicated for this reason, Metformin can also help some people regulate their cycles.

People with PCOS may be able to regulate their menstrual cycle through weight loss, changes to their diet, and exercise.

In addition, the dietary supplement inositol has been shown to be helpful to regulate periods and balance hormones in women with PCOS. 

If your periods suddenly become irregular or if they've never been regular, you should bring this to your healthcare provider’s attention. Further diagnostic testing and/or medical intervention may be necessary.


People with PCOS often experience irregular periods. If you have PCOS, you might have unpredictable periods or a cycle that is unusually long.

PCOS isn't the only cause of irregular periods. You may also have irregular periods if you've recently started menstruating or are approaching menopause. Certain other medical conditions can also cause irregular periods.

Treatment for PCOS-related irregular periods varies, though weight loss and other lifestyle changes can help. Your healthcare provider can help you decide if other treatments, like medication, are right for you.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Faghfoori Z, Fazelian S, Shadnoush M, Goodarzi R. Nutritional management in women with polycystic ovary syndrome: A review study. Diabetes Metab Syndr. 2017;11 Suppl 1:S429-S432. doi:10.1016/j.dsx.2017.03.030

By Nicole Galan, RN
Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book."