First published
The menstrual cycle is a complex biological process that involves the cyclical maturation and release of an egg, controlled by a delicate interplay of hormones. While the hormonal changes during the menstrual cycle are primarily associated with reproductive function, they can also have significant effects on metabolism.
One such effect is on blood sugar levels and insulin resistance, which can vary across the menstrual cycle. Understanding these variations is important, as they may have implications for the management of conditions such as diabetes and polycystic ovary syndrome (PCOS) in women.
In this article, we will explore the relationship between the menstrual cycle, blood sugar levels, and insulin resistance, and discuss the potential implications for women's health.
The menstrual cycle is the process of ovulation and menstruation, which occurs on average every 28 days in most women. The cycle is regulated by a complex interplay of hormones, including estrogen and progesterone.
These hormones are responsible for preparing the uterus for pregnancy, as well as causing changes in the ovaries and other organs.
The menstrual cycle consists of two main phases: the follicular phase (approx days 1-14) and the luteal phase (approx days 15-28). Understanding the different phases of the menstrual cycle is essential in understanding the relationship between the menstrual cycle and glucose levels.
You can learn more about it in our in-depth article about The Menstrual Cycle – Phases, hormones, and their functions
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Historically, studies on how blood sugar levels change during the menstrual cycle have had mixed results. Some research shows that blood sugar changes with the cycle, especially during the luteal phase (after ovulation), while others found no significant changes. However, its important to note that these studies have had issues like small numbers of blood sugar tests, reliance on self-reported dates for menstruation, and not accounting for differences in body weight or physical activity, which could explain why the results vary from one study to another.
A more recent study conducted in August 2023, has shown that:
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They found that sugar levels were highest during the Luteal phase (after ovulation, before menstruation) and lowest during the Late Follicular phase (just before Ovulation). These changes were consistent even when considering other factors like physical activity, estrogen levels, food cravings, tiredness, and sleep problems.
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The study's findings support the idea that hormones like estrogen, which vary during the menstrual cycle, can affect metabolism and blood sugar levels. For instance, estrogen can reduce appetite and food cravings, which might help explain why blood sugar levels and food cravings vary during the cycle.
The study also suggests that daily blood sugar levels could be used to estimate different phases of the menstrual cycle. This could help people, particularly those with conditions like diabetes, to adjust their diets, sleep, or insulin therapy based on their menstrual cycle. However, it’s worth noting that women with diabetes may experience more significant changes in blood sugar levels during the menstrual cycle than women without diabetes.
As mentioned before, different stages of the menstrual cycle can have different effects on your blood sugar levels. Blood sugar levels are at their highest during the Luteal phase and start to descend during menstruation, reaching their lowest point in the Late Follicular phase. As you approach the luteal phase, these blood sugar levels naturally increase even further and you may experience some insulin resistance. Several studies ( have shown that a high concentration of progesterone is related to abnormal glucose metabolism, a high level of plasma glucose, and increased insulin resistance.
As we already know, the menstrual cycle is a huge combination of changing hormones. We mentioned in the previous section, how blood sugar levels change in the menstrual cycle. Now let us dig a little further into the hormones responsible for blood sugar levels.
The hormone that is responsible for increasing your blood sugar is glucagon. Glucagon comes from alpha cells found in the pancreas, their primary function is to work with other hormones and bodily functions to control glucose levels in the blood. In simple terms, they increase blood sugar levels when they go too low.
The hormone that is responsible for decreasing your blood sugar is insulin. A cell's ability to absorb glucose is mediated by insulin, which allows the muscle, fat, and liver to absorb glucose from the blood. Glucose can serve as energy or be converted into fat as needed.
Yes, high insulin levels can cause irregular periods. This is because insulin is a hormone that helps to regulate the menstrual cycle. When insulin levels are too high, it can disrupt the normal balance of hormones, which can lead to irregular periods.
There's no single cause of insulin resistance. Instead, it's a combination of certain genetic and lifestyle factors that can lead to the condition. These include:
These are the general factors that can trigger insulin resistance, In the next section we shall talk more about how the menstrual cycle has a hand in insulin resistance.
There is some evidence that ovulation may cause insulin resistance. One study found that women who ovulated had higher levels of insulin and C-peptide (a marker for insulin resistance) than women who did not ovulate.
Moreover, the study “Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis” found that women with Polycystic Ovarian Syndrome (PCOS), are often associated with insulin resistance and defects in insulin secretion, which explains the increased prevalence of glucose intolerance in PCOS.
These studies suggest that there may be a link between ovulation and insulin resistance, but more research is needed to confirm this. If you're concerned about your risk of insulin resistance, talk to your healthcare provider
As mentioned in a previous section, insulin sensitivity is higher in the follicular phase (pre-ovulation) and decreased in the luteal phase (post-ovulation).
Studies also show that, during the luteal phase, there would be an increase in circulating insulin and a reduction in circulating glucose and triglycerides.
A few major factors that can worsen insulin resistance are
While it is almost impossible to completely cure insulin resistance. However, you can help your body’s cells become more receptive to insulin by
Hormone changes, especially during your menstrual cycle, can affect a person's diabetes. Hormonal fluctuations and hormonal imbalances cause blood glucose and insulin fluctuations. So women with diabetes should take extra care in managing these changes.
Several factors can influence blood sugar levels during menstruation. One of the most significant factors is diet and nutrition.
Studies have shown that women who consume a diet high in carbohydrates and processed foods may experience greater blood sugar fluctuations during the menstrual cycle.
Recent studies suggest that regular physical activity (PA) can lower the risk of insulin resistance. Exercise with higher energy expenditure such as high-intensity interval training (HIIT), produces greater results. However, both aerobic and resistance exercises can improve glucose regulation.
You can read the study review here: Update on the effects of physical activity on insulin sensitivity in humans
Other factors that may influence blood sugar levels during the menstrual cycle include medications and other health conditions.
Managing blood sugar levels during the menstrual cycle can be challenging, but there are several strategies that women can use to help regulate their blood sugar levels. One of the most important strategies is to eat a healthy diet. Women should consume foods that are low in carbohydrates and high in fiber, such as whole grains, fruits, and vegetables.
Regular exercise can also help to regulate blood sugar levels during menstruation. Women should aim to get at least 150 minutes of moderate-intensity exercise per week. Other strategies for managing blood sugar levels during the menstrual cycle include managing stress, getting adequate sleep, and taking medications as prescribed.
Tracking blood sugar during the menstrual cycle can be done using a blood glucose meter or continuous glucose monitoring system (CGM).
These devices can provide real-time information on blood sugar levels and help identify patterns and fluctuations over time. It's also important to keep a menstrual cycle calendar or app to track the menstrual cycle phases and note any changes in blood sugar levels.
This information can help in adjusting diet, exercise, and medication to manage blood sugar levels during the menstrual cycle. It's important to consult with a healthcare provider for guidance on tracking and managing blood sugar levels during the menstrual cycle.
Here are a few simple, lifestyle changes that can help improve your blood sugar levels.
Lifestyle changes:
Diet guidelines:
In summary, the menstrual cycle can have a significant impact on blood sugar levels in women, particularly during the luteal phase of the cycle.
Women with diabetes should monitor their blood sugar levels regularly and take steps to manage their blood sugar levels. By understanding the relationship between the menstrual cycle and glucose levels and adopting healthy lifestyle habits, women can improve their overall health and well-being.
Founder of Elara Care and O.A. Dip. Certified Women's Health Practitioner, Jas is working to create better solutions for women since 2018, sharing her struggles and experiences with female health
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Dr Natalie, PhD, MPhil - Sports Science Research Specialist investigating the menstrual cycle in sports, ranging from participation to elite sports performance. Swansea University Lecturer.
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