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Variations in Menstrual Flow

Menstruation, by definition, comes with flow—the cyclical discharge of the uterine lining. Just like is says on the packaging of feminine hygiene products, your flow can be light, heavy, or “normal.” But normal will be different for different bodies.

Differences in Menstrual Blood Flow

Your menstrual flow is determined by many factors: hormone levels, the physical structure of your uterus and your body, stress, physical activity, and other factors. Various medical conditions can also affect your period. If you are experiencing extremely heavy periods, irregular periods, or strong symptoms, go see your doctor or gynaecologist to rule out potential problems.

From the onset of puberty until the arrival of menopause, a woman will, on average, experience around 450 menstrual cycles. Periods can be regular and irregular, and this can change over time. Changes in diet, stress levels, or overall health can influence even the most reliable period on occasion, and that is completely normal.


Period Tracker & Calendar

You can track your period using WomanLog. Download WomanLog now:
You can track your period using WomanLog. Download WomanLog now:

It can sometimes be hard to understand if your period “looks like it’s supposed to”, let alone wrap your head around which period products to use. This becomes less surprising when you know that period products were tested with real blood for the first time only in 2023! Deeply rooted stigma and misinformation around this topic still exist in our communities, so let’s have another look at period flow basics.

What is normal period flow?

Menstruation is the cyclical shedding of the uterine lining. You have probably heard that the amount of blood shed with each period is quite small—only about 60 millilitres or 4 tablespoons—even though you cramp and bleed for days. For heavy periods, the average amount of menstrual blood lost over the whole period is closer to 80 millilitres or 5,5 tablespoons.

Menstrual blood (plus vaginal secretions and endometrial cells) is expelled from the uterus through involuntary uterine contractions. It doesn’t flow in a steady stream but comes in intermittent drips, trickles, and spurts over the course of several days. This process is not influenced by the position of your body or by contracting the pelvic muscles.

Once it begins, the active bleeding period of the menstrual cycle usually lasts from 3 to 7 days, or until the process is complete. If your period is over 10 days long, check in with a doctor to rule out any underlying issues, but even 10 days can be completely normal.

Many people, especially those who have never experienced a period, still hold misconceptions about how period flow behaves. For example, some people think that women can hold in their period blood like urine and release it at will. In fact, menstruation is triggered by an abrupt decline in the hormone progesterone, which is the body’s normal response to not having gotten pregnant during the fertility window around ovulation, and the discharge happens completely automatically.

What is period blood like?

The colour of menstrual blood ranges from bright red to dark brown and changes over the course of your period. At the beginning it is usually bright red, the colour of fresh blood, and usually darkens and thickens slightly as the days go by and the blood oxidizes. Brownish blood is very common towards the end of your period.

Period discharge may also contain some small, jelly-like clots. These are common and nothing to worry about. However, if you see large clots, experience frequent clotting, or have other concerns about the consistency of your menstrual blood, consult your doctor or gynaecologist.

Period blood normally has a slight odour but should not have a strong or foul smell. If you notice an unusual or unpleasant odour, it could be a sign of infection or some other health issue.

Defining Light, Moderate, and Heavy Period Flow

What counts as light, moderate, and heavy period flow?

Most periods start with a few “warning drops” or a trickle that increases in volume over the first few days as your uterus activates to clear out the endometrial lining.

To manage a moderate flow, you will need to change your tampon or pad, or empty your menstrual cup, every 3 to 5 hours or so. Different brands can vary in size and absorbency, so it can take some trial-and-error before you figure out what works best for you.

For a light flow, you can use light absorbency products and may only need to change them once or twice a day, while a heavy flow will require greater absorbency and you may be switching them out every two hours. To avoid the rare possibility of Toxic Shock Syndrome, don’t use the same tampon for more than 8 hours, even if your flow is very light. It’s fine to sleep with a tampon.

If you experience leaks, even when you are changing often enough for your flow, you might want to try a using a higher absorbency product or try a brand with a different shape. Many people double up and use a pad or liner together with a tampon or menstrual cup.

Heavy bleeding that soaks through tampons or pads quickly, especially when accompanied by dizziness, nausea, or fainting, should be discussed with your healthcare provider.

Heavy flow, or menorrhagia, is very common; up to 30% of women report experiencing heavy periods regularly. This is generally down to genetic factors and is absolutely normal. However, a heavier menstrual flow slightly increases the risk for iron deficiency and anaemia and can also sometimes be caused by:

  • hormone imbalance
  • uterine fibroids
  • infection
  • PCOS
  • IUD use
  • certain medications
  • stress and other lifestyle factors

Important! If your period seems unusually heavy, it is always better to check in with a doctor to rule out serious health complications. Internal bleeding caused by conditions such as kidney failure or ectopic pregnancy can sometimes be mistaken for menstrual bleeding, so if you suspect something is wrong, it’s better to trust your intuition and ask for medical help, even if you discover it’s not serious, than to let a serious condition develop untreated.

Identifying Days of Heaviest Period Flow

On which days is period flow heaviest?

Most women report their blood flow at its heaviest at the start of their period, usually the first two to three days. The amount generally tapers off after that but can intensify again just before the end.

Most women agree that trusting your period flow to decrease steadily isn’t wise. A surprise resurgence is always possible—and absolutely normal.

Why is my period so light?

If your period is usually light, this is probably just what a period looks like for your body. It is normal for the amount of discharge to vary or skip a day and then return. Even if your flow is light, stay on guard until the end. It’s usually a safe bet that after seven days your period is over, but it can last slightly longer, so maybe leave that white pantsuit in your closet another day or two—just in case.

If your flow is suddenly much lighter than usual, don’t worry too much but be on the lookout for other changes in your body and health.

The most common reasons a period becomes lighter than usual include:

  • stress
  • eating disorders
  • thyroid disease
  • pregnancy
  • breastfeeding
  • perimenopause

An unexpectedly heavy or light period can be a sign of early pregnancy. In that case it’s not really a period at all, it just looks like one.

Polycystic ovary syndrome, or PCOS, can be another reason for unusually heavy or light periods because it causes elevated androgen levels that disrupt the usual course of the menstrual cycle. This condition should be taken seriously but can often be successfully managed. If your period is wildly unpredictable, visit your gynaecologist to find out what’s going on.


How can I increase my period flow?

If your periods are naturally light, there is no need to worry about increasing the flow. Blood loss is still blood loss and encouraging it might actually be dangerous.

If your period has become lighter because of stress, poor diet, anaemia, or a health disorder, there are steps you can take to rebalance your system. Stress management and a wholesome diet are foundational for period health and for your health in general. Drink plenty of water, eat some fruits and vegetables every day, and make sure to include foods rich in iron and fibre in your diet.

Turmeric, ginger, cinnamon, beetroot, and foods that are rich in Vitamin C and antioxidants are considered beneficial for menstrual flow and improving the regularity of your cycle.

In some cases, hormonal therapy may be prescribed by a healthcare provider to regulate menstrual flow. This is typically done when there is an imbalance, such as low oestrogen levels. Similarly, a thyroid disorder or PCOS can have an impact on menstrual flow. Consult a healthcare provider to find out how to manage the symptoms.

Does light period flow mean infertility?

Another myth people sometimes come across is that a heavy period means you are more fertile. While it’s true that your body generates a fresh uterine lining prior to ovulation every month—like putting fresh sheets on the guest bed in case you have company—having more or less regular cycles is better indicator of fertility than the heaviness of menstrual flow, and simply having “fresh sheets” is more important that what those sheets look like.

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