Irregular periods are never normal. We’re shocked at how many patients come to us thinking their history of irregular or sporadic menstrual cycles was not a major red flag from the get-go. If you’re not having a period on a regular, trackable schedule, then you’re not ovulating regularly.

10 Common Causes of Unpredictable Periods

The more honest women are with their gynecologists about whether or not they’re getting their periods regularly, the sooner we will be able to manage and treat common reproductive issues before they become significant infertility factors.

The average female menstrual cycle (from the day you start your period to the day before you start the next one) is 23 to 35 days. If you never keep track, we recommend using a wellness app that tracks periods to make sure you’re not skipping periods without noticing it.

Here are some of the most common causes of unpredictable or irregular periods.

1. Residual birth control hormones

If you’ve just stopped using the pill or a hormonal birth control shot, or you’ve recently removed a hormonal patch, IUD or implant, there’s a chance residual ovulation-blocking hormones are still at play. We recommend giving your body at least 90 days to return to its natural reproductive hormone balance.

If you’re not having regular periods 90 days after ceasing hormonal birth control, contact your OB/GYN and look into it.

2. You’re pregnant

Of course, one of the most common reasons women stop having a period is because they’re pregnant. Today’s home pregnancy tests are fairly accurate but can still give a false negative result. We recommend waiting two weeks and trying again OR scheduling an appointment with your physician, OB/GYN, or a local clinic for a lab-tested sample so you can be sure.

3. Endometriosis

Also one of the most common causes of infertility, endometriosis, affects roughly 11% of the female population. It’s caused when endometrial tissue (the tissue that lines the uterus and sheds during periods) winds up in places that it shouldn’t be – such as the exterior of the uterus, fallopian tubes, ovaries, or even on other pelvic and abdominal tissues.

It can cause more painful period symptoms, heavier or abnormal period flow, and spotting in between periods. It can also cause periods to be far longer than normal in duration. Interestingly, the degree of endometriosis doesn’t correlate to whether or not it affects fertility. However, managing endometriosis through diet, hormonal birth control, and surgery (if endometrial lesions need to be removed) minimizes symptoms and improves fertility chances when you’re ready to get pregnant.

3. Polycystic ovarian syndrome (PCOS)

Women with PCOS tend to have higher androgen levels (male hormone), and irregular periods are common because they don’t ovulate. Some women with PCOS never have periods at all, while others ovulate and bleed very infrequently. It is another common cause of infertility.

Managing PCOS also helps minimize PCOS side effects that compromise fertility, like the tendency to be overweight or insulin resistance that commonly leads to developing type 2 diabetes.

4. Being underweight or overweight

Did you know that being underweight can be even worse for fertility than being overweight? Women with disordered eating and extreme athletes commonly experience skipped periods. Or, as a result of the physical strain on the body – and related hormone imbalances – they may stop ovulating altogether.

5. You’re in perimenopause

Menopause marks the end of a woman’s reproductive years, evidenced by at least 12 consecutive months without getting a period. The average age for reaching menopause is 51, but the lead-up to menopause, called perimenopause, can begin ten years prior. Perimenopause is not the same thing as early menopause.

Perimenopause is entirely normal, and it’s not uncommon for women to start having more frequent periods (shorter cycles) or missed periods as early as their early to mid-40s. If you’re 43 or older and notice periods aren’t as consistent as they used to be, mention it at your next well-woman exam. Odds are, it’s the beginning of perimenopause.

6. Early (premature) menopause or diminished ovarian reserve

Early menopause, also called premature menopause, is another cause of irregular periods. In this case, a younger woman’s body has significantly fewer eggs (diminished ovarian reserve) than most women her age. As a result, her body may begin going into menopause during her 30s, and she may reach full menopause before 45.

Sometimes, premature menopause or lower egg reserves are genetic. Other times, it is due to health issues or medication side effects. If you plan to delay starting a family until your mid to later 30s or early 40s, we recommend testing your egg reserves. This information is essential for creating your fertility plan and determining whether you should freeze and store eggs for later use.

7. Cancer or certain medical treatments

Sometimes, certain cancers, medical conditions, or aggressive medical treatments threaten fertility or take a toll on ovarian reserves. Because egg quality is essential to a healthy, full-term pregnancy and baby, specialists should always discuss any significant medical diagnosis or treatment with you to determine whether it threatens fertility. If so, fertility preservation is an option but should happen before any threatening surgeries or treatments.

8. Age-related diminished ovarian reserve

The amount of viable eggs dramatically declines after a woman turns 36. These days, as more women choose to put off starting their families, we’re seeing higher rates of age-related diminished ovarian deserve. If you would rather not use fertility treatments to get pregnant, we recommend creating fertility plans that optimize conception at home before egg quantity and quality become a problem.

Otherwise, egg freezing is the best way to ensure your fertility chances are the same as the age you were when you froze the eggs.

9. Stress levels

It used to be that “stress” was considered an anecdotal reason for infertility. However, several studies now correlate elevated stress hormones with infertility. It seems that psychological stress can impact fertility even more than physical survival stress (malnourishment, nomadic lifestyles, extreme living conditions, etc.).

This is why we strongly encourage patients to make healthy lifestyle changes that support fertility, including stress management, to give their bodies the best chance.

10. Fibroid tumors

Fibroid tumors are benign (non-cancerous) tumors growing in or on the uterus. In some cases, fibroids interrupt endometrial development, resulting in abnormal periods depending on the type of fibroids you have and where they’re located. Fibroids are very common, but they’re worth knowing about and keeping an eye on to minimize their impact on ovulation and fertility.

RRC Treats Causes of Irregular Periods & Infertility

Do you have a history of irregular periods? Schedule an appointment with your OB/GYN so they can listen to your history and determine the cause. Schedule a consultation with the Reproductive Resource Center if you’ve tried to get pregnant without success for 12 months or more if you’re 36 or older. We’re the region’s #1 fertility center because we prioritize accurate diagnosis and personalized treatment plans.