5 Potential causes of irregular periods

Wellness gurus tout the benefits of cycle syncing and tracking for many reasons, but if you’re having issues with how and when your cycle shows up, it can be frustrating. One month it's early, the next it's late — and sometimes it barely shows up at all.

While it can be alarming, irregular periods are actually pretty common. In fact, studies estimate that anywhere from 14% to 25% of women of childbearing age experience some form of menstrual irregularity. But "common" doesn't mean you should brush it off, “An irregular cycle is a signal that something is off hormonally,” counsels Gouri Pimputkar DO FACOOG, DipABLM.  Your menstrual cycle can tell you a lot about what's going on with your hormones, your metabolism, and your overall health.

‍

What is an irregular period?

A typical menstrual cycle runs somewhere between 21 and 35 days. Bleeding usually lasts about 3 to 7 days. When your cycle consistently falls outside that window or varies wildly from month to month, you might have irregular periods.

Irregular periods can look like: 

• Cycles that are shorter than 21 days or longer than 35 days
• Missing three or more periods in a row
• A flow that's significantly heavier or lighter than usual, spotting between periods, or cycle lengths that swing dramatically from month to month.

An occasional off-cycle is usually nothing to worry about. Persistent irregularity, though, often signals something worth investigating.

‍

5 Potential causes of irregular periods

‍

Cause #1: Polycystic Ovary Syndrome (PCOS)

PCOS is one of the most common hormonal conditions affecting women of reproductive age, affecting between 10 and 13% of reproductive-aged women.

Irregular periods are often one of the first signs of PCOS because the ovaries produce higher-than-normal levels of androgens (male hormones), which can prevent or delay ovulation. Delayed ovulation means an unpredictable period. 

The good news: PCOS is manageable. Hormonal support, lifestyle changes, and targeted nutrition can all help regulate the cycle and support ovulation.

‍

Cause #2: Thyroid disorders

Your thyroid does a lot more than most people realize — including playing a direct role in regulating your menstrual cycle. Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can throw your cycle off in different ways, making periods heavier, lighter, more frequent, or less frequent than normal.

In some cases, thyroid dysfunction can even stop ovulation entirely. On top of that, thyroid disorders are notoriously underdiagnosed. “Thyroid dysfunction is chronically underdiagnosed in women,” shares Dr. Pimputkar. “But menstrual cycle changes are an early sign, so if you’re experiencing that alongside fatigue, weight shifts, or brain fog, your thyroid should absolutely be part of the conversation," she continues, especially in women. 

Getting your thyroid levels checked is a smart first step.

‍

Cause #3: Chronic Stress

Yes, stress can actually mess with your period, among other things. Chronic stress means elevated levels of the stress hormone cortisol, which can interfere with the hormones responsible for triggering ovulation. 

Research shows that women who experience high levels of chronic stress are more likely to develop amenorrhea, meaning their periods stop altogether. This might also be an evolutionary tactic, as stress signals that now might not be a safe time to reproduce — so it deprioritizes the reproductive system.

‍

Cause #4: Endometriosis

Endometriosis is another relatively common condition that affects around 1 in 10 women of reproductive age. 

In Endometriosis, tissue similar to the uterine lining grows outside the uterus, often on the ovaries, fallopian tubes, or surrounding tissue. The abnormal growths can cause a range of menstrual irregularities, including unusually heavy bleeding, spotting between periods, and severe cramping or pelvic pain. It’s also one of the leading causes of infertility.

‍

Cause #5: Weight changes, disordered eating, and over-exercising

Your body needs a certain amount of energy and body fat to maintain regular ovulation. When external factors such as rapid weight gain or loss, undereating, or excessive exercise disrupt that balance, your cycle can go haywire.

Hypothalamic amenorrhea is caused by being significantly underweight, having a very low body fat percentage, or dealing with an eating disorder. In exercise-induced amenorrhea, athletes or those with intense exercise regimens start skipping periods due to excessive exercise, high metabolic stress, and low caloric intake. 

On the flip side, excess body fat can lead to elevated estrogen levels that disrupt the cycle in a different way.

‍

Other factors that can affect your cycle

A few other common contributors are worth knowing about. Coming off hormonal birth control can cause irregularity for several months as your body recalibrates — this is especially common after stopping the pill or getting an IUD removed. 

Elevated prolactin levels (a hormone primarily associated with milk production) can also disrupt the cycle by throwing other reproductive hormones off balance. And as women enter perimenopause, they have more irregular periods than usual due to fluctuating estrogen and progesterone levels.

‍

Irregular periods and infertility

Irregular periods themselves don't cause infertility, but they're often a sign of unpredictable or absent ovulation. And without ovulation, conception isn't possible. “Irregular periods don't automatically mean infertility, but you should make it a point to identify what’s driving that irregularity,” explains Dr. Pimputkar.

The conditions behind irregular cycles — PCOS, thyroid dysfunction, endometriosis — can each affect fertility in their own way. But most of these conditions are treatable. Identifying and addressing the root cause early puts you in a much stronger position, whether pregnancy is on your radar now or somewhere down the line.

‍

When to ralk to a provider

Dr. Pimputkar notes, if your periods have been consistently irregular, you deserve answers. “Women deserve to understand what's happening in their own bodies. You don’t have to just live with this.”

Diagnostic testing, such as a thorough hormone panel, can reveal a lot: thyroid function, estrogen and progesterone levels, androgen levels, metabolic markers, and more. From there, your provider can work with you to build a care plan that addresses root causes rather than just symptom management.

At Allara, we take a comprehensive approach to hormone health — which means looking at the full picture of what's driving your symptoms, so we can get to the bottom of what’s really going on.

Take the guesswork out of irregular periods and sign up for Allara today.

‍

Irregular periods FAQ

‍

Can irregular periods cause infertility?

It's a fair question — and the honest answer is: it depends on what's causing the irregularity. Irregular periods themselves don't cause infertility, but they're often a sign of unpredictable or absent ovulation. And without ovulation, conception isn't possible.

The conditions behind irregular cycles — PCOS, thyroid dysfunction, endometriosis — can each affect fertility in their own way. But most of these conditions are treatable. Identifying and addressing the root cause early puts you in a much stronger position, whether pregnancy is on your radar now or somewhere down the line.

‍

Does endometriosis cause irregular periods?

Yes, it can — though its effects on cycle timing vary from person to person. What's more consistent is the pain. If your periods are not only unpredictable but also intensely painful, endometriosis is something to bring up with your provider.

‍

What are the Causes for Irregular Periods​?

Irregular periods can stem from a number of different hormonal and health-related factors. The most common causes include PCOS, thyroid disorders, chronic stress, endometriosis, and significant changes in weight or exercise habits. Starting or stopping hormonal birth control can also affect your cycle, as well as life stages like perimenopause. It’s best to speak with a healthcare provider to determine the underlying cause before attempting a treatment plan.

‍