Can irregular periods cause infertility?

Medically reviewed on February 17, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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A person’s menstrual cycle is an important facet of their fertility awareness, especially if planning for pregnancy. If you want to become pregnant, knowing when you’re ovulating during the menstrual cycle can help to optimize the chances of conception.

But if periods are irregular, it may be more difficult to determine when exactly you’re ovulating each month, or if you’re ovulating at all. In fact, you may wonder, can irregular periods cause infertility?

While irregular periods are a potential sign of infertility, they’re not always related [1].

In this article, we’ll define what an irregular menstrual cycle is, how they may impact your fertility, and what to do to address them and increase the chances of conceiving. (Consider taking the at-home Women's Fertility Test to learn more about your fertility-related hormones.)


What’s an irregular period?

Every person’s menstrual cycle is slightly different. It's a little challenging to establish what a regular period is, but on average, a regular menstrual cycle lasts between 21 and 35 days [2]. However, even if a menstrual cycle varies by a few days month-to-month, it’s still considered regular.

In contrast, irregular periods include [2]:

  • Menstrual cycles that are shorter than 21 days
  • Menstrual cycles that last longer than 35 days
  • Menstrual cycles that vary by more than a few days each month
  • Periods that last longer than seven days
  • Extremely heavy periods

If you occasionally have an irregular menstrual cycle, it’s usually not a cause for concern. However, if your period’s irregularity persists for more than three months, you may want to schedule an appointment with a healthcare provider.

Do irregular periods impact fertility?

If periods are irregular, you might worry about your fertility. While irregular periods may indicate infertility, this isn’t always the case. Many people still get pregnant despite having irregular periods. However, it can be more difficult.

Here are some reasons why [2]:

  • Anovulation – Irregular periods are a potential sign of anovulation. Anovulation is when ovulation doesn’t occur during a menstrual cycle, meaning that an egg isn’t released. If there’s no egg, there’s nothing for a sperm to fertilize, so pregnancy can’t happen.
  • Unpredictable ovulation – Even if you’re ovulating, having irregular periods may make it harder for you to predict which days you're ovulating each month. As a result, it may be harder to maximize the chances of getting pregnant.

How to check for an irregular period

If you don’t pay much attention to your menstrual cycle, you may not even realize that your periods are irregular. You can monitor the regularity of your periods by tracking them.

To track periods:

  • Write down the date of the first day of your period each month
  • Calculate how long each menstrual cycle lasts, from one period’s start date to the next
  • See if your cycles vary notably in length

You can also use period-tracking apps on a mobile phone for added convenience. If you notice menstrual irregularities occurring often, you can choose to see a specialist and/or take an at-home fertility test.

What causes irregular periods?

If a menstrual cycle is irregular, you may wonder why. Here are a few common causes of menstrual irregularity:

Polycystic ovary syndrome (PCOS) – PCOS is a hormonal disorder that affects between 6–12% of reproductive-aged people [3]. This condition is often painful because it causes the ovaries to become enlarged and develop cysts. Common symptoms of PCOS include [4]:

  • Irregular periods
  • Acne
  • Weight gain
  • Excessive hair growth
  • Infertility

Having PCOS while pregnant may increase the risk of miscarriage or premature delivery [5]. Because of this, it’s a good idea to get checked for PCOS before pregnancy if you’re experiencing any of these symptoms.

Lifestyle factors – Sudden or extreme changes to your lifestyle can also offset the menstrual cycle. Some potential lifestyle factors to investigate include:

  • Excessive exercise
  • Stress
  • Poor diet
  • Weight fluctuations
  • Travel
  • Changes in birth control

Other health conditions – In addition to PCOS, thyroid imbalances, diabetes, endometriosis, eating disorders, obesity, hyperprolactinemia, and certain sexually transmitted infections can result in irregular periods [2].

Some of these reasons for irregular periods may impact fertility, whereas others may not. Your healthcare provider can help you determine if the root cause of your irregular periods is impacting your fertility and reproductive health.

How to treat irregular periods

If you’re trying to get pregnant, regulating periods may be possible with the right treatment plan. Depending on the cause of irregular periods, you can potentially help get them back on track by [6]:

  • Reducing your stress levels
  • Cutting back on excessive exercise
  • Improving your diet
  • Losing or gaining weight
  • Taking medications to treat underlying conditions
  • Taking fertility medications to induce ovulation

Monitor your fertility from home with Everlywell

If you’re worried that your irregular periods are a sign of infertility, you can check your hormone levels from home using a fertility test from Everlywell. Our Women’s Fertility Test measures five key hormones that can affect ovulation and menstrual cycle regulation, such as:

  • Estradiol
  • Luteinizing hormone
  • Follicle-stimulating hormone
  • Thyroid-stimulating hormone
  • Total Testosterone

If you discover that these hormones are out of balance, you and a healthcare provider can develop a proactive treatment plan to restore fertility and period regularity.

What is secondary infertility?

Thyroid and fertility

Fertility awareness methods

When to see a fertility specialist

What affects fertility?


1. What are some possible causes of female infertility? National Institutes of Health. URL. Accessed February 17, 2022.

2. What are menstrual irregularities? National Institutes of Health. URL. Accessed February 17, 2022.

3. Polycystic Ovary Syndrome. American College of Obstetricians and Gynecologists. URL. Accessed February 17, 2022.

4. Polycystic Ovary Syndrome (PCOS). American College of Obstetricians and Gynecologists. URL. Accessed February 17, 2022.

5. Katulski K, Czyzyk A, Podfigurna-Stopa A, Genazzani AR, Meczekalski B. Pregnancy complications in polycystic ovary syndrome patients. Gynecol Endocrinol. 2015 Feb;31(2):87-91. Epub 2014 Oct 30. PMID: 25356655.

6. What are the common treatments for menstrual irregularities? National Institutes of Health. URL. Accessed February 17, 2022.

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