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Can losing weight affect your period?
How weight loss someone's period will vary from person to person, but your periods might become irregular, more or less frequent, lighter, or heavier than usual.
Medically reviewed by
Craig Marsh, Specialist Pharmacist Prescriber (UK)
- Weight loss can cause hormonal shifts, which can influence your periods.
- Losing weight can cause your periods to become lighter, shorter, heavier, irregular, or to stop altogether.
- Eating a healthy diet, getting enough sleep, and staying active can help manage changes in your period.
How does weight affect your menstrual cycle?
Your menstrual cycle is controlled by complex interactions between your brain and your ovaries (called the hypothalamic-pituitary-ovarian axis). Having overweight or obesity can affect your hormone levels, which can cause missed periods or, in other cases, heavy menstrual bleeding.
When you’re dealing with obesity or overweight, having increased body fat (especially around your waist) can cause your body to produce too much estrogen. This can hinder ovulation and cause irregular or missed periods.
On the other hand, if you’re experiencing heavy bleeding, it could be linked to abdominal fat (particularly a type called visceral fat). This can cause your body to make more hormones involved in inflammation, like cytokines and adipokines. Inflammation can slow down how fast your uterus heals after each period and increase the amount of blood you lose during menstruation.
In many cases, losing extra weight can help make your menstrual cycle more regular.
But losing too much weight to the point where you’re underweight isn’t good either, and can cause your period to stop altogether. This is common in athletes or women with eating disorders. For regular periods, your body typically requires a minimum of 22% body fat.
In what ways can weight loss change your period?
There are many ways in which both losing weight can lead to changes in your menstrual cycle. These depend on how your body reacts to weight loss, and will differ from person to person. You can find a list below:
- Lighter periods: Weight loss puts stress on the body, and both the weight loss itself and the injections can cause complex hormonal changes that lead to lighter bleeding.
- Shorter periods: Hormonal fluctuations can also make your period shorter than usual, but this will vary from person to person.
- Heavier periods: Losing a lot of weight can cause your estrogen levels to fluctuate. This can increase blood flow to your uterine lining, thickening it and leading to heavier periods.
- Irregular periods: This is because your body may take rapid weight loss, especially when paired with low nutrition, as a sign of stress. This can throw off your hormonal balance and ovulation, leading to missed or irregular periods.
- Longer periods: This, again, is because of hormonal imbalances, in particular estrogen, which can cause your uterine lining to become thicker, making your periods longer and heavier.
- PMS symptoms: Losing weight and eating healthily can ease PMS symptoms like cramping or bloating.
More research is needed to understand why these happen and identify the factors that can help predict what will happen specifically.
What can be done if you experience period changes due to weight loss?
If you notice changes in your period after losing weight, it’s important to keep track of what’s happening to your body. If you’re concerned, reach out to your clinician. Period changes may not always be linked to weight loss, they could be caused by something else. It’s always a good idea to speak with a doctor to rule out any underlying medical conditions.
How can period changes be managed?
If your period changes aren’t too concerning and you don’t feel the need to see a physician, there are still a few things you can do to manage them:
- Eat a healthy, balanced diet, get enough sleep, and exercise regularly, as these can all impact your menstrual cycle.
- If you experience any pain or discomfort, discuss treatment options with a medical professional.
- Keep track of your periods. If you’re worried about any changes in your periods like longer, shorter, or heavier cycles, contact your clinician for advice.
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