The Hidden Link Between Irregular Periods and Insulin Resistance

Key Takeaways

• Irregular or long menstrual cycles can be an early sign of insulin resistance, which may increase the risk of developing type 2 diabetes and PCOS. 
• Lifestyle changes, such as balanced eating, regular exercise, and routine blood sugar monitoring, can improve insulin sensitivity, restore regular periods, and reduce long-term health risks.
• Even if you don’t meet the full criteria for PCOS, tracking your cycle and health can help you identify early imbalances and seek early intervention. 

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Many factors can contribute to irregular periods, ranging from perimenopause, thyroid dysfunction, birth control pills, and hormonal changes due to polycystic ovary syndrome (PCOS) or endometriosis, to name just a few.¹

Irregular or longer than normal menstrual cycles affect about 20% of reproductive-age women.² 

One often overlooked cause is insulin resistance, an important factor that may progress to the development of type 2 diabetes. The ovaries (which secrete hormones that regulate your period) are particularly sensitive to insulin changes.^1,2,3 

Determining the root cause of irregular periods can help treat underlying conditions and prevent metabolic health issues, such as insulin resistance, diabetes, and PCOS. 

In this article, you’ll learn about the link between irregular menstrual cycles and insulin resistance, including how hormonal imbalances and conditions like polycystic ovary syndrome (PCOS) can affect reproductive and metabolic health. Learn practical, research-based strategies to manage these health issues.

Understanding Insulin Resistance

Insulin resistance occurs when the body doesn’t respond to insulin like it should. When working correctly, insulin is a hormone made by the pancreas to help the body use energy properly.⁴

After you eat or drink foods with carbohydrates, the digestive system breaks carbohydrates into glucose or sugar and then releases sugar into the blood. Insulin is released from the pancreas in response to increased blood sugar levels.⁵ 

Insulin allows the cells to take in glucose from the blood, causing the blood glucose level to decrease appropriately as it is used for energy. Blood sugar levels change throughout the day.⁵

When your blood sugar is consistently elevated, some part of the process is malfunctioning. If your blood glucose level keeps rising, you may develop pre-diabetes or type 2 diabetes.⁴ Your blood sugar level reflects how well your body converts food into energy. Any alterations should be investigated further. 

About 87 million American adults (approximately half are women) do not know they have prediabetes or type 2 diabetes. That equates to one in four adults in America. Prediabetes puts you at increased risk for developing type 2 diabetes, heart disease, and stroke. Over 70% of people with prediabetes go on to develop type 2 diabetes.⁶  

Certain risk factors are associated with insulin resistance (and prediabetes), including:

• Excess weight or a larger waist size
• Being 35 years or older
• Family history of diabetes
• Being African American, American Indian, Asian American, Hispanic, Latino, or Pacific Islander
• Physical inactivity (sedentary lifestyle)
• Smoking or being exposed to secondhand smoke
• History of gestational diabetes, or giving birth to a baby weighing 9 pounds or more
• Having other conditions like PCOS, Cushing’s syndrome, acromegaly, sleep apnea, or a viral disease like COVID-19
• Taking certain medications over time (glucocorticoids, antipsychotics, and HIV medications)⁴ 

While you can’t change some of these risk factors, you can make lifestyle changes to reduce many, preventing reproductive and metabolic complications of insulin resistance. 

How Insulin Resistance Affects the Menstrual Cycle

The exact causes of irregular menstrual cycles due to hormonal imbalances are not entirely understood, but research points to abnormal hormone levels that involve insulin resistance. 

As mentioned earlier, insulin helps to shuttle energy (glucose) from your bloodstream to cells requiring energy so they can work well. When your cells resist this process, your body may make extra insulin to compensate.³

High insulin levels cause the ovaries to make too much testosterone, interfering with follicle development and preventing regular ovulation (egg production and release).³ 

Without ovulation, cycle length increases past the normal length of 28 days, with research reporting that up to 77% of women with PCOS have cycle lengths longer than three months.⁷  

Insulin resistance can lead to weight gain, and excess fat can cause the body to produce even more insulin, exacerbating hormonal problems and creating a vicious cycle. 

Pinpointing the root cause of your hormonal imbalances and irregular periods is critical for optimal well-being and metabolic health. 

The Role of PCOS in Menstrual Irregularities

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects about 5 to 8% of all reproductive-age women. Women with PCOS have a significantly increased risk of insulin resistance, abnormal lipid levels, type 2 diabetes, heart disease, and altered glucose metabolism.⁷

Researchers have investigated whether the severity of menstrual irregularities and the degree of insulin resistance are correlated in 494 women with PCOS. They found that over 80% of the women had infrequent periods lasting longer than three months.⁷ 

Longer menstrual cycles were linked to high insulin resistance, especially for women with cycles longer than three months. Women with normal cycle lengths had no increased insulin resistance compared to controls. Researchers proposed that irregular periods should be used as a screening feature for possible insulin resistance.⁷ 

A prospective cohort study of over 75,000 women from 2020 found that women with consistently irregular or prolonged menstrual cycles had a significantly higher risk (32 to 66% greater risk depending on age) of developing type 2 diabetes, especially if they had a poor diet, carried excess weight, and had low physical activity.² 

Common symptoms of PCOS include:

• Irregular periods (or no periods at all)
• Difficulty getting pregnant
• Excessive hair growth
• Weight gain
• Thinning and hair loss on the head
• Oily skin and acne

Many of these symptoms become apparent in the late teens or early twenties. Many women are diagnosed when they struggle to get pregnant. Work with your healthcare provider if you have any of the common symptoms or concerns about your periods or overall health.³

Diagnostic criteria for PCOS require at least two of the following three features (known as the Rotterdam criteria):

• Irregular periods, infrequent, or absent periods (indicating your ovaries do not ovulate)
• Clinical signs or blood tests indicating high androgen levels (excess facial/body hair, acne, or high testosterone blood tests)
• Scans showing polycystic ovaries (usually at least 12 follicles in each ovary)³

Some women may not meet full diagnostic criteria for PCOS but still show signs of insulin resistance. Monitoring overall health, including menstrual patterns, energy levels, and lab work, can help identify early warning signs of insulin resistance, diabetes, or hormonal imbalances.

Recognizing the Signs of Insulin Resistance

People with insulin resistance and prediabetes often have no obvious symptoms or the symptoms emerge gradually, making it hard to recognize any changes. 

However, there are more subtle signs and symptoms of insulin resistance:

• Darkened skin on the neck, armpits, or groin (acanthosis nigricans)
• Some people have type 2 diabetes symptoms, but usually, the body is still working well enough.
• A1C (average blood sugar level over past 3 months) of 5.7% to 6.4%⁸

Here are some common signs and symptoms of type 2 diabetes, including worsened insulin resistance:

• Weight gain
• Fatigue
• Increased thirst or hunger
• Frequent urination
• Frequent infections
• Vision changes
• Numbness or tingling in the feet or hands
• A1C greater than 6.5%⁸

Pay attention to signs and symptoms of insulin resistance, prediabetes, and diabetes in conjunction with irregular menstrual cycles. Menstrual cycle changes reflect hormonal changes and should be addressed to prevent further progression.^2,7 

Strategies for Managing Insulin Resistance and Restoring Menstrual Regularity

With practical lifestyle and diet changes, you can stop the vicious cycle of insulin resistance and its impact on your reproductive health. 

Many management and treatment strategies effectively lower insulin and blood glucose levels, helping restore reproductive health. Every person is unique and may find some approaches more effective. 

Here are some changes to improve your reproductive and metabolic health:

1. Achieving a lower body weight (even just a 5% weight loss) can significantly improve PCOS, blood sugar levels, and insulin management.³ Weight loss helps your body process carbohydrates better and improves insulin sensitivity. Weight loss can be achieved through diet, activity, and sleep improvements. 

2. The American Diabetes Association encourages the adoption of a balanced diet, such as the Diabetes Plate Method. This easy-to-use visual is a great first step to improving your nutrition and balancing your macronutrients to reduce blood sugar and insulin levels. You divide a 9-inch plate into three sections: half is non-starchy vegetables (like asparagus, broccoli, lettuce, carrots, and celery), one-quarter is lean protein foods (like fish, chicken, lean beef, cheese, nuts, and beans), and one-quarter is foods with high-fiber carbohydrates (like whole grains, brown rice, oatmeal, corn, potatoes, beans, and fruits). Beverages include water or other low or no-calorie drinks.⁹ 

3. Regular physical activity is beneficial for preventing type 2 diabetes and helping control blood glucose levels. Regular movement helps your cells become more sensitive to insulin, which works better to lower your blood sugar levels.¹⁰ Research indicates that regular exercise should be considered a first-line treatment for women with PCOS and can improve menstrual regularity, insulin sensitivity, heart disease risk factors, and mental health.¹¹ Current guidelines recommend at least 150 minutes of physical activity per week. To reach 150 minutes over the next couple of months, start small, aiming for at least 30 minutes of exercise 2 to 3 times a week. 

4. Stay aware of your blood sugar levels. Women with PCOS have altered glucose metabolism that leads to insulin resistance and eventually type 2 diabetes. Annual blood sugar tests, like the A1C test, which measures your average blood sugar levels over the past three to four months, can help identify changes that may indicate pre-diabetes and help you get your numbers under control. If you have other diabetes risk factors, more frequent monitoring may be needed.

5. Medicines may be needed to treat symptoms of PCOS. Work with a healthcare provider knowledgeable about PCOS to discuss appropriate medications for you. They may consider metformin or other medicines to help with insulin resistance or medications to help with unwanted hair growth.

Adopting a healthy lifestyle, which may include medical management, a balanced diet, regular exercise, and consistent blood sugar monitoring, will support you in managing PCOS and insulin resistance and promote overall well-being.

When to Seek Medical Advice

Regular medical monitoring and sharing health changes with your healthcare provider can help you feel your best and achieve optimal metabolic and reproductive health. 

If you are experiencing irregular or absent periods, excess hair growth, difficulty getting pregnant, have noticed blood sugar or insulin changes, or are concerned with any menstrual issues, you should see your healthcare provider for a complete evaluation to help diagnose the root cause of your concerns and discuss treatment options. 

The Bottom Line

Irregular periods are often more than an inconvenience; they can signal an underlying issue that may be caused by insulin resistance or PCOS, which increases your risk for type 2 diabetes.

Paying attention to your cycle length and patterns can indicate early metabolic and reproductive health changes.

Fortunately, lifestyle strategies like balanced nutrition, regular exercise, and routine blood sugar monitoring offer proactive steps toward restoring hormonal balance and preventing long-term complications. 

Learn More With Signos’ Expert Advice

Maintaining healthy blood sugar levels is essential to long-term health. Certain health conditions, like PCOS and insulin resistance, require more careful attention to eating and exercise to support metabolic health.

A Signos continuous glucose monitor (CGM) allows you to track your blood sugar levels in real-time, helping you understand how diet, food choices, and exercise affect your body and levels. These positive changes can help you improve your health, prevent type 2 diabetes, and lose weight. 

Learn more about nutrition and health tips on Signos’ blog, written by health and nutrition experts.