How much blood do we lose on our periods?

During our fertile years, our bodies are destined to constantly ride the merry-go-round known as the menstrual cycle. This cycle prepares our bodies for pregnancy by thickening the endometrium and bringing an egg to maturity, ready for fertilisation.

The endometrium is packed full of blood cells to nurture the fertilised egg. However, if pregnancy doesn’t occur, the endometrium sheds, rupturing the blood cells, causing 3-5 days of bleeding known as a period.

It’s not just blood in our period through; your menstrual fluid is also made up of endometrial tissue, mucus and blood clots, all of which can change the volume and consistency of your monthly.

How much blood do we typically lose on our periods?

The average person will have around 500 periods in their lifetime and lose roughly 30-40 millilitres (two-three tablespoons) each cycle. However, the span of what is considered a normal amount of period blood is vast. Some studies even suggest that up to 60 millilitres of menstrual blood (four tablespoons) is acceptable.

The amount of blood a person loses each period can often change from month to month and can be much lighter or heavier depending on several factors.

How to measure your period blood

You may not need to measure your period blood to tell if your flow is lighter or heavier than usual; however, if you’re curious, hygiene products can help you estimate how much blood you lose each month.

The easiest way to measure your period bloodis by using a menstrual cup. Some cups even contain markings for more straightforward measurement and can hold between 30-60 millilitres at a time. All you need to do is take note of how much blood is in your menstrual cup each time you empty it. Then, add up these numbers to find your total blood loss. Continue logging your period blood over three or four cycles; this should provide you with an idea of how much blood you lose on an average cycle.

Tampons, pads and period panties make it a little harder to measure your period blood. The first thing to do is take into account the product’s maximum capacity. For example, regular tampons can hold 5 millilitres of fluid. If you lose around 60 millilitres of blood, you will go through about 6-12 tampons, depending on the size used.

To measure your period blood with tampons, pads and period panties, take into account:

• The capacity of the product
• How often you change it
• How full it is when you change it

Again, tracking this over 3-4 cycles will help to determine your average blood loss.

What if you have a heavy flow?

Some people have a naturally heavier flow meaning they lose a larger amount of blood. However, a heavy flow can also be a sign of an underlying condition or a side effect of medication.

Heavy flows can be caused by:

• Interuterine devices (IUDs)
• Polycystic ovarian syndrome
• Endometriosis
• Pelvic inflammatory disease
• Uterine fibroids
• Polyps
• Adenomyosis
• Hypothyroidism
• Bleeding disorders
• Certain medications

What if you have a lighter flow?

Lighter periods than normal are not always a cause for concern. A light flow is usually characterised by minor bleeding, a shorter duration of period or light bleeding or spotting that is consistent throughout the period. A lighter period may also come with fewer PMS symptoms such as back pain, cramping and mood swings.

Lighter flows can be caused by a number of factors such as:

• Excessive exercise
• Age
• Being underweight
• Stress
• Medical conditions
• Pregnancy
• A lack of ovulation
• A side effect of birth control or other medications

When to see a doctor

While changes in blood loss are not usually worrying, if you notice that your period becomes consistently light or heavy or you miss your periods altogether, then a doctor’s consult will be required to diagnose the cause.

Tracking your menstrual cycle via an app can help you log the start and end of your periods and enable you to keep track of any symptoms. This will ultimately help a doctor to diagnose and treat any issues you may have.