What is Normal Menstrual Flow and What Can Cause It to Change?

Jul 01, 2023

Vineeta Agrawal

What is Normal Menstrual Flow and What Can Cause It to Change?

Every person who menstruates experiences a unique menstrual cycle. Understanding what constitutes a normal period flow and the factors that can influence it is essential for women's health. In this blog, we will deliver what defines a normal period flow and explore the various reasons why menstrual cycles can change.

What is a normal period flow?

A normal period flow refers to the amount of blood a person typically loses during their menstrual cycle. On average, a menstrual cycle lasts around 28 days, although variations are common. The actual bleeding period, known as menstruation, typically lasts for 3 to 7 days. The amount of blood lost during this time can vary but is generally between 30 to 80 milliliters (ml), or approximately 2 to 16 tablespoons.

It is important to note that what is considered normal can differ among individuals. Factors such as age, overall health, and contraceptive methods used can influence menstrual flow. It is also common for period flow to vary slightly from month to month.

What causes the menstrual cycle to change?

  1. Hormonal fluctuations: The menstrual cycle is regulated by hormones, particularly estrogen and progesterone. Any disruption in their balance can impact the regularity and flow of menstruation. Hormonal changes can occur due to factors such as stress, puberty, pregnancy, perimenopause, and certain medical conditions.
  1. Contraceptive methods: The use of hormonal contraceptives, such as birth control pills, patches, or intrauterine devices (IUDs), can affect menstrual flow. These methods often result in lighter and shorter periods. Conversely, certain contraceptives, such as the copper IUD, may lead to heavier or more prolonged bleeding.
  1. Medications: Some medications, including anticoagulants, anti-inflammatory drugs, and certain antidepressants, can affect the menstrual cycle. It is important to consult with a healthcare professional about the potential side effects of any medications you are taking.
  1. Stress: High levels of stress can disrupt the delicate hormonal balance, leading to changes in menstrual flow. Stress can also cause skipped or delayed periods. Engaging in stress-reducing activities, such as exercise, meditation, and adequate sleep, can help maintain a regular menstrual cycle.
  1. Weight fluctuations: Significant weight loss or gain can impact hormone production and subsequently affect menstrual flow. Both being underweight and overweight can lead to irregular or absent periods. Maintaining a healthy weight through balanced nutrition and regular exercise can support a regular menstrual cycle.
  1. Medical conditions: Certain medical conditions, such as polycystic ovary syndrome (PCOS), endometriosis, uterine fibroids, and thyroid disorders, can cause changes in menstrual flow. These conditions may result in heavier or prolonged periods or conversely, lighter and shorter periods. Consulting with a healthcare professional is important for proper diagnosis and management of these conditions.


Understanding what constitutes a normal period flow and recognizing the factors that can influence menstrual cycles is vital for maintaining women's health. While there is considerable variation in what is considered normal, it is important to pay attention to significant changes in menstrual flow. Consulting with a healthcare professional can provide valuable guidance and support for any concerns related to menstrual health.


Q: What is a good menstrual flow?

A: A good menstrual flow varies among individuals, but it generally refers to a regular cycle with a moderate amount of bleeding that is neither too heavy nor too light.

Q: How much blood is normal for a period?

A: The average amount of blood lost during menstruation ranges from 30 to 80 milliliters (ml), or approximately 2 to 16 tablespoons. However, individual variations are common.

Q: Does heavy flow mean fertile?

A: A heavy flow does not necessarily indicate fertility. The heaviness of menstrual flow primarily depends on various factors such as hormone levels, uterine lining thickness, and underlying medical conditions. Fertility is determined by the ability to conceive, which may or may not be affected by the flow of menstruation.