What we’ll cover:

• Everyday factors that can cause changes to your cycle
• How GLP-1 medications may impact your periods
• Tracking changes in your cycle
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You may have read that the average menstrual cycle lasts for 28 days. However, variations of this are more common than you may think. Cycles often range from 21 to 35 days on average. Your period responds to what is happening inside your body. This means it can change from month to month depending on several factors. 
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Why changes can occur

A regular cycle depends on a fine balance of different reproductive hormones. Several everyday factors can disrupt this balance. This can be temporarily or over a longer period of time. This may include:

• Stress and mental well-being
• Poor sleep or changes to the circadian rhythm (which can happen in shift workers)
• Rapid weight loss or weight gain
• Over-exercising (especially high intensity workouts) and under-fuelling
• Underlying conditions such as endometriosis and polyendocrine metabolic ovarian syndrome (PMOS - formerly known as PCOS)
• Hormonal contraception
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How can GLP-1 medications impact the menstrual cycle?

GLP-1 medications are currently licensed to treat Type 2 Diabetes and obesity. However, some women may notice changes to their cycle as an indirect result of taking a GLP-1 medication. Depending on the individual, these changes may make periods more regular, or cause a temporary period of irregularity.
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Improved menstrual regularity 

Studies show that women with a higher body mass index (BMI) are more likely to have irregular cycles. Even moderate weight loss (around 5-10% of body weight) can help. For example, by improving insulin sensitivity and reducing inflammation.

While weight loss is possible without GLP-1 medications, doing it without medical support can be very tough for women with PMOS especially. However, recent research suggests that GLP-1 medications can help to significantly improve menstrual regularity in women with or without PMOS.

It is important to note that this may also improve fertility outcomes for some. However, more research is needed into this area and GLP-1 medications should not be used when trying to conceive or throughout pregnancy. Your GP or prescriber can provide guidance on contraception recommendations for different weight management medications.
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Menstrual irregularity 

GLP-1 medications often lead to faster weight loss than gradual lifestyle changes alone. If you lose a high percentage of weight too quickly, your period frequency may change.

Your body needs energy and key nutrients from food. For example, it needs healthy fats to support your hormones and keep your cycle regular. This is why pairing GLP-1 medications with nutrition support is so important. It ensures you eat a balanced, varied diet that supports your hormones as your body changes.
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What to do if you notice new changes in your cycle‍‍

You know your body best. If something does not feel right, we recommend speaking with your GP and informing your clinician or prescriber. Tracking your cycle over a few months is a great way to track changes and symptoms. You can do this with an app or a paper/ digital diary. If you develop any bleeding after sex or breakthrough bleeding in between cycles, it is important to talk to your GP or prescriber a bit sooner.
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Summary

Your cycle responds to stress, diet, and metabolism changes. GLP-1 medications can improve period regularity by improving insulin sensitivity and supporting weight loss. However, rapid weight loss may disrupt timing (temporarily). Pairing treatment with balanced nutrition ensures your body gets the key fuel it needs to support a regular cycle.‍