How Much Blood Loss During Period Is Normal?

For most women, their period is a cause for much concern. You may be wondering about whether your menstrual cycle is normal, and whether there is any way to calculate how much blood loss during period you undergo. Depending on the results, you can make informed choices if you need to consult a doctor.

On average, period cycles last for about 28 days. The cycle should ideally last between 21 to 35 days, with a couple of days’ variations per month, this is considered normal. Menstruation itself lasts between 3 to 7 days on average. Some women might have naturally heavier bleeding, so it is advisable to be familiar with your own cycle and its characteristics. This will facilitate the detection of any untoward changes if any. 

Blood Loss During Period: What Constitutes Heavy Blood Loss?

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Blood loss during menstruation comprises about 30 to 50 millilitres of blood, which works out to two or three tablespoons. At the start of menstruation, there are heavier flow days while towards the end, the flow becomes lighter. It is also considered normal to expel small-sized clots.

Heavy blood flow or excessive bleeding is known as Menorrhagia. A woman is said to suffer from Menorrhagia when the blood loss during menstruation is more than 80 ml or 5 tablespoons. Yet another indicator of excessive bleeding are clots bigger than one inch in diameter.

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Moreover, if your period lasts for more than seven days, it can lead to heavy flow and is regarded as abnormal. Some women also suffer from Polymenorrhea, or cycles that occur in less than 21 days, leading to frequent menstruation.

Excessive blood loss can lead to losing blood cells, thereby causing iron deficiency and Anaemia resulting in weakness and dizziness.

An Estimate of How Much Blood Loss During Period

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It is possible to calculate how much blood has been lost during period. This depends on the kind of period or menstruation product used.

1. If you use tampons, then to calculate how much blood loss during period, you should keep a log of how many tampons you have used and how soaked they are before you changed them. It is worthwhile to remember that regular-sized tampons can absorb 5 ml of blood whereas extra-absorbent ones can hold approximately 10 ml of blood. 

It is advisable to change your tampon every four to six hours and not wait until they are fully soaked.

2. If you use sanitary pads, remember that the capacity of pads depends on the models and brands. However, on an average, a regular-sized pad can hold the same amount as a tampon – 5 ml of blood, and an extra-absorbent pad can hold 10 ml of blood. Blood constitutes about 36% of your flow while mucus and other fluids comprise of 64% of your flow. Therefore, to calculate blood loss, this factor has to be taken into account.

To get an estimate of your actual blood loss, multiply the number of sanitary pads used by either 5 ml (for regular-sized pads) or 10 ml (for extra-absorbent pads). The resultant number must be multiplied by 0.36 to get the amount of blood loss.

3. If you use menstrual cups, it is relatively easy to calculate the amount of blood loss. Most menstrual cups have measuring marks on them, or on the packaging. Relevant Information is also available on the brand website.

The causes of heavy blood flow include endometriosis, thyroid problems, intra-uterine devices (IUD), and others. If you suffer from excessive blood loss, as determined by calculating how much blood loss during period, don’t hesitate to see your doctor. 

References: Heathline, Flo