What is a "normal" period?

Common does not equate normal when it comes to our healthcare, and our periods are no exception.

Understanding and tracking your menstrual cycle can be an important signal of endocrinological health. An individual’s period is considered normal and healthy if it falls within the range typical for a series of components, including cycle length, amount of blood, and more. An irregular period may be a sign of a hormonal imbalance.

As you learn about periods, it is important to remember that healthy menstrual cycles vary widely between individuals. Periods tend to change across an individual’s lifetime due to hormonal fluctuations associated with aging.

Lastly, menstrual cycles can vary widely with contraceptive use; hormonal supplementation can help change what is considered “regular” for an individual.

Periods 101: Our menstrual cycle & abnormal uterine bleeding

Before jumping in to what a normal vs. abnormal period is, let’s start with the basics.

What is the menstrual cycle?

Our menstrual cycle is catalyzed by monthly hormonal fluctuations that occur in people with ovaries to prepare for potential pregnancies. This encompasses the cyclical pattern of preparing for ovulation, ovulating, preparing the uterus for a pregnancy, and at last shedding our uterine lining with a period if we are not impregnated during a particular cycle.  

What hormones are responsible for our menstrual cycle?

Each month, our ovaries release an egg in hope of pregnancy (yep, that’s right - even if you don’t want to get pregnant, it’s what your reproductive system is aiming for each month!).

While essentially all of our hormones play into this, including non “reproductive” hormones like our thyroid, insulin, and cortisol, we will be focusing on the 4 major reproductive hormone players here: follicle-stimulating-hormone (FSH), estrogen, luteinizing hormone (LH), and progesterone.

  • Follicle-stimulating hormone (FSH): FSH is produced by our brain and responsible for stimulating our ovaries to product “follicles” that will subsequently produce estrogen. It is particularly important in the first days of our cycle, before ovulation occurs.  
  • Estrogen: Estrogen, perhaps the most well-known female sex hormone, increases pre-ovulation with the development of the aforementioned follicles. It keeps increasing until your body is close to ovulation, when it produces…
  • Luteinizing hormone (LH): When estrogen levels are high enough to ovulate, our brain triggers a “surge” of LH, which is ultimately responsible for pressing “go” on ovulation at around day 14 of our cycle. Our bodies generally release 1 egg per cycle from a “dominant” follicle that has produced a strong egg (if it releases more, we enter the realm of non-identical twins or triplets if implantation occurs for a particular cycle).
  • Progesterone: Once the dominant follicle has ovulated and sent its egg through our fallopian tubes and into our uterus, it turns its attention to progesterone production. It is now called a corpus luteum. While progesterone has several functions, its main role is to build up the uterine lining in advance of a pregnancy. If implantation does not occur, the corpus luteum will disintegrate and result in a fairly rapid drop in progesterone. This is ultimately what triggers our period.
Period cycles menstrual cycle phases

What is abnormal uterine bleeding (AUB)?

Abnormal uterine bleeding (AUB) is the general term describing atypical menstruation in which bleeding is abnormal in cycle length, bleeding duration, or schedule.

To understand what is “abnormal,” we first must explore the components of the menstrual cycle.

  • CYCLE LENGTH: Menstrual cycle length is the time period from the first day of your period to the following cycle's first day. This cycle length can range from 21 to 35 days. A longer cycle length is more common in the first few years when individuals begin menstruating, and the "normal" length of a cycle for teens is 21 to 45 days. With age, individuals’ cycles tend to become more regular and shorter in length.
  • DAYS SPENT BLEEDING: Within a menstrual cycle, the period of bleeding should range from 3 to 7 days of bleeding, depending on each individual.
  • MENSTRUATION-RELATED SYMPTOMS: Some moderate physical or emotional symptoms are normal for individuals throughout the menstrual cycle. When this occurs before our period, it is often referred to as premenstrual syndrome, or PMS. Pain, breast tenderness, bloating, acne, fatigue, mood swings, irritability, anxiety, insomnia, and other sleep disturbances are often reported in the week leading up to one’s period and during the bleeding phase. While some extent of these symptoms can be “normal” PMS or period symptoms and all are certainly “common,” no period symptoms should interrupt your day-to-day life. Although it is less common, it is important to be aware of Premenstrual Dysphoric Disorder (PMDD), which is a condition in which some individuals consistently have more severe symptoms associated with their menstruation. If your symptoms become severe or impede daily functioning, your healthcare provider can help you manage these concerns.
  • AMOUNT OF BLOOD: The typical amount of bleeding each cycle varies greatly between individuals. The average amount of blood lost is about 30 to 60 milliliters, which is about two to four tablespoons. Heavy menstrual bleeding is considered 80 milliliters or more of menstrual blood lost each month.
  • BLOOD COLOR: Some variation in the color of our period blood is normal, while others may be cause for concern.

What can cause a disruption in a normal period?

There are a variety of catalysts that can lead to period loss or an abnormal period.

Abnormal bleeding can be influenced by a variety of factors such as high prolactin, DHEA-S, or 17-hydroxy progesterone. We’ve explored many of these topics on our blog before:

I think my menstrual cycle is abnormal. Now what?

If you are trying to identify whether your period is “normal,” you may feel a bit overwhelmed. We’ve covered a lot of data points in this article, and it can be difficult to keep track of everything.

For that reason, we recommend you try cycle tracking for several weeks or months. You can record the following factors for several months in a row - either with an app or in a journal - in order to get a sense of persistent irregularities:

  • Cycle length between period start dates
  • Number of days of bleeding
  • Changes in blood flow (heaviness, presence of blood clots)
  • Abnormal bleeding between periods
  • Abnormal pain or other significant symptomology changes

Lastly, it is likely time to see a healthcare provider if you have been experiencing:

  • Period loss for more than 90 days and you’re not pregnant
  • An erratic period cycle or length after having been regular
  • Bleeding between periods or after menopause
  • If you’re bleeding while pregnant
  • Bleeding for more than 7 days
  • Severe pain during or between periods
  • Severe heavy bleeding (i.e., soaking through more than one pad or tampon every one to two hours)
  • Menstrual cycles outside the 21 to 35 day length
  • Sudden fever and nausea after using tampons

Abnormal periods can be very confusing. Pollie is here to help you understand and manage your menstrual health. For more information on menstrual cycles and how to find your “perfect provider”, read our blog and get started as a member today. Also, if your abnormal periods are due to having PCOS, be sure to join our digital PCOS product.


Jocelyn Spizman

Jocelyn is a certified crisis counselor and health journalist passionate about integrative healthcare, plant-based nutrition, and socio-cultural determinants of health. She double majored in Human Health at Emory University and aspires to make biomedicine more digestible and explore cultural wellness phenomena.