Fainting during your period is a common symptom affecting many women. Young women in their teens and 20s are most likely to be affected as their body acclimatises to the fluctuating hormone levels. There are several factors that may cause you to faint during your period: vasovagal syncope, low blood sugar and prostaglandins.


Prostaglandins are chemicals produced by the endometrium (lining of the uterus). During your period, these prostaglandins are released. If you have particularly heavy periods, very high levels of prostaglandins can be released which can cause period pains, nausea and vasodilation (temporary widening of the blood vessels). This can lead to decreased blood pressure, which limits the amount of oxygen that reaches your brain. Your brain is very sensitive to oxygen levels so may cause you to faint in order to restore the blood flow and oxygen levels it needs. Vasodilation caused by prostaglandins can lead to vasovagal syncope.

Vasovagal Syncope

Vasovagal syncope is fainting caused by overstimulation of the nerves (vagus nerve). The vagus nerve runs down the centre of your body, connecting many of your organs. It is involved in regulating many important functions such as heart rate and blood pressure. Reduced blood pressure can lead to fainting.

Low Blood Sugar

The fluctuations of your hormone levels during your period can also cause a brief period of low blood sugar, even if you are not diabetic. This can also contribute to vasovagal syncope. Ensuring you avoid high sugar foods, and eating carbohydrates that release their energy slowly, may help you to maintain a more stable blood sugar level. It’s also a good idea to ensure you eat three proper meals a day and have a cereal bar or snack to hand if you need it.


Iron-deficiency (anaemia), is a common contributing factor to fainting during periods. Iron helps your blood carry oxygen. If you do not have enough iron, your body will not be able to carry as much oxygen in the blood as it would normally. Therefore, your chances of fainting may be higher than if you had the correct levels of iron. A doctor will be able to verify iron-deficiency (anaemia) with a simple blood test. It is very common amongst younger women, especially if they are relatively tall and slim or vegetarian/vegan. A doctor may prescribe you iron tablets or recommend you eat plenty of iron-rich foods such as red meat or spinach, depending upon the severity of your deficiency.

How to stop fainting during your period

If you find yourself fainting on your period, Ibuprofen can be a very effective way to reduce the prostaglandins and their effects, whilst also alleviating any pain you experience. Ibuprofen is an anti-inflammatory drug and a pain-killer. It reduces the amount of prostaglandins, reducing the chance that your blood pressure will drop and that you will faint.

During your period, eat well and regularly. Drink lots of water and ensure you have ibuprofen to hand. Be aware of your symptoms and if you feel like you are going to faint, sit down or ideally lie down and raise your legs in the air (placing them on a chair can while you lie on the floor is a good idea. When you feel better, sit up slowly, sip some water and eat some carbohydrates if possible to restore your energy levels.


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