Last week I wrote about period tracking – what to track and why it is important.
This post is all about normal menstrual cycle patterns. Tracking will help you identify what is happening with your menstrual cycle, but interpretation of those patterns requires an understanding of what is considered normal. In this post we will cover the following components of your menstrual cycle, with an emphasis on normal presentation.
- Menstruation length, blood loss, and period pain
- Flow assessment
- Bleeding between periods
- Day 1 of your period
- Menstrual cycle length and regularity in an adult vs a teen
- Consistency and colour of menstrual fluid
- Hormonal balance
- Why ovulating is crucial for your menstrual cycle
- How to track your physical signs of ovulation: fertility awareness method
- Premenstrual syndrome
I wrote briefly about normal menstruation length, blood loss, and period pain in an earlier post, 5 things you should know about your cycle. Here’s a recap.
Normal menstruation length is 3-7 days (4-5 days is average). Normal blood loss is 25-60 ml (50 ml is average). To visualize this, one soaked normal-sized tampon or pad holds a teaspoon (5 ml) of blood. Depending on the model, a menstrual cup holds about 2 tbsp (30 ml) of blood.
Menstruation should occur virtually symptom free. Most women feel bloating or a heavy sensation. A little bit of cramping on day one is considered normal. Normal period pain should improve with NSAIDs and analgesics, and it should not interfere with your daily activities.
Flow can be assessed roughly by the number of pads or tampons used daily, but that’s not always accurate since women differ in their definitions of heavy, moderate, or light flow. Do you usually soak a pad or tampon, or spot it lightly? Adjust your count accordingly. The same can be said for a menstrual cup. If not filled, adjust the count. Also, do you use a pad and tampon at the same time? You should not have to change your pad or tampon more than once every two hours during the day. And at night your flow should slow so that you don’t have to get up to change your pad.
Bleeding between periodsIn terms of bleeding between periods, have you noticed mid-cycle bleeding, premenstrual bleeding or bleeding after intercourse? In some cases, these bleeding patterns can be normal and harmless; however, in other cases, bleeding between periods can be a sign of a more serious gynaecological condition such as uterine fibroids, endometriosis, pelvic infection, or uterine polyps. If you are unsure as to the cause of your bleeding, please see your doctor.
Day 1 of your period
When I ask a patient about her menstrual cycle, I start with the date of her last menstrual bleed, or put differently, when was day 1 of her last period. Day 1 of your period is the first day of heavy bleeding, not spotting. For many women, this day is often the most painful. As her flow slows, cramping and pain usually decrease.
Menstrual cycle length and regularity
The next important piece of information is the length of her menstrual cycles (from “day 1” to the next “day 1”). Period tracking apps are especially helpful for recording this type of information. It is hard for anyone to recall when their last period was, let alone the last 3 or 6 periods. Just enter your first day of heavy bleeding as “day 1” of your period in your tracking app. After a few months you will see if there is variation in your cycle length. As an adult, a healthy menstrual cycle is anywhere between 21 to 35 days, with 28 days being the average. The key here is that every woman is different. What is your normal? A regular cycle should not vary, meaning day 1 of your period arrives every “x” number of days, on average. If it’s 21 days one cycle, then 32 days the following cycle, then 25 days and so on, then that’s considered an irregular cycle. It is important to note that teenagers have longer cycles. It can take up to 12 twelve years to develop a mature menstrual cycle. A healthy menstrual cycle between 21 to 45 days is considered normal for a teenager. Longer cycles for a teen is considered normal because it can take up to 12 years to develop a mature menstrual cycle, regular ovulation and an optimal level of progesterone (according to Dr. Jerilynn C. Prior, a Canadian endocrinologist with expertise in reproductive hormones). This is an important consideration for girls who take hormonal birth control to regulate their cycles.
Just FYI, missed, early, or late periods are also considered signs of an irregular cycle.
Consistency and colour of menstrual fluid
Your menstrual fluid should be a reddish-brown colour because blood turns darker when it is exposed to air. And unlike normal dark reddish-brown menstrual discharge, excessive flow tends to be bright red and may include clots.”Your menstrual fluid should be mostly liquid, with no large clots. As your uterine lining breaks away and sheds, your body releases natural anticoagulants to thin it and help it to flow more easily. If you flow heavily, then you may form a few clots because the anticoagulants do not have time to do their job. Menstrual clots are normal, but they should be few and fairly small: about the size of a dime (1.8 cm).” – Briden, Lara. “Period Repair Manual: Natural Treatment for Better Hormones and Better Periods.” iBooks.
Overall, your uterine lining should be fairly easy to shed. But that depends on having adequate progesterone levels, which depends on the health of the corpus luteum.
The corpus luteum is the final stage of your follicle’s 100-day journey to ovulation. Ovarian follicles are sacs within your ovaries that contain the eggs. As they develop, these follicles produce estrogen, progesterone, and testosterone. These hormones determine how you progress through all the menstrual cycle phases to your menstrual flow or period.
It takes approximately 100 days for ovarian follicles to mature from a dormant state all the way to ovulation. Ovulation occurs when one dominant follicle (rarely two) finally ruptures and releases an egg. After ovulation, the emptied follicle restructures itself into a progesterone-secreting gland called the corpus luteum. Healthy follicles => production of estrogen, progesterone, and testosterone => ovulation => healthy corpus luteum => more progesterone => hold and nourish a pregnancy OR healthy period
By healthy period I mean it arrives on time, with no PMS symptoms in the luteal phase, no premenstrual bleeding or spotting, and your uterine lining is in good shape (well-formed and not too thick or inflamed, and fairly easy to shed).
Therefore a healthy period depends on having optimal progesterone levels.
With enough progesterone, your period will arrive smoothly, with no premenstrual symptoms, spotting or pain. Progesterone counterbalances estrogen. It thins your uterine lining, whereas estradiol stimulates your uterine lining to grow and thicken. The more estradiol you have, the thicker your uterine lining, and the heavier your period will eventually be. That is why unopposed estrogen due to low progesterone or estrogen excess will result in symptoms like heavy bleeding. That is true whether you have a relative excess (ie too much estradiol because progesterone levels are low) or a true excess of estradiol levels (usually due to impaired estrogen metabolism or detoxification). We need both hormones in balance because they both have specific and, usually opposite, roles in regulating the menstrual cycle.
The importance of ovulation. Do you ovulate? When it comes down to it, a healthy cycle is all about ovulation. Ovulation matters because it’s how you make progesterone. Progesterone is important for keeping estrogen in check. It’s also beneficial for mood, metabolism, and bone health.
But how do you know if you’ve ovulated? Just because you get a period every month doesn’t mean that you ovulate every month. These are known as anovulatory bleeds. Anovulatory cycles are common with PCOS and peri-menopause, but they can occur occasionally at any time or during stressful times, like over exercising and under eating (calories or carbohydrates). Implant and injection methods of hormonal birth control also suppress ovulation. Pill bleeds are drug withdrawal bleeds from synthetic estrogen and progestin. If you take the pill then you do not ovulate.
Going back to our question about ovulation, the fertility awareness method (FAM) is a way to track your physical signs of ovulation. It requires observation and tracking of three fertility signs: basal body temperature, cervical mucus, and cervical position changes. This is different from the rhythm method which solely relies on dates on the calendar. FAM helps you learn about your cycle, your body and how it changes throughout your cycle. But how do you do FAM and is it right for you? Talk to a healthcare professional about your options and make sure you are using fertility awareness correctly. You can also check out the 2015 American College of Obstetricians and Gynecologist (ACOG) statement about fertility awareness method here.
Here are a few points to get you familiar with the concept of FAM
- Basal body temperature (BBT) tracking: Oral temperature is taken upon waking and before getting out of bed. For consistency, take your temperature at the same time each day (weekends too!) Your temperature should increase with increasing progesterone levels during the luteal phase of your cycle (see image below). With a healthy corpus luteum, you will see 11 to 16 “high-temperature” days between ovulation and the first day of your period. I say “high temperature” in quotations because they’re not “high” per se. Do not expect huge temperature shifts with this. The temperature shifts are subtle, but when graphed reveal a distinct pattern. BBT tracking can tell you a lot about your cycle, but it is NOT a good predictor of ovulation since the temperature shifts after ovulation. But it can tell you if ovulation is occurring. Downloadable charts for tracking can be found here.
Source: Hall, J.E. 2019. Yen and Jaffe’s Reproductive Endocrinology, 8th Edition. Physiology, Pathophysiology, and Clinical Management; Chapter 7 – Neuroendocrine Control of the Menstrual Cycle, Pages 149-166.e5. Available online 22 February 2018.
- Cervical mucus changes throughout a cycle are normal and healthy. It can be used to track ovulation and fertility for a woman who wants to track her cycle. For example, fertile mucus is like egg whites; rich in water, inorganic salts, and mucin, which forms a gel that keeps the cervical canal open. Itlasts approximately 3-5 days (can be 1 day), is stretchy like egg whites, discharged in copious amounts (women will report feeling wet), and forms a symmetrical circular spot on underwear. Infertile mucus on the other hand can be dry, watery, milky, sticky, or crumbly.
- Cervical position: If you are comfortable checking the texture and position of your cervix, then you will notice that in the days just before ovulation it will be higher and softer. Otherwise, it sits low (about one finger length inside your vagina) and it feels hard like the tip of your nose.
Once you know when and if you’ve ovulated, you can expect your period 10 to 16 days later. Unless you are pregnant, your luteal phase can never be more than 16 days. That’s because your corpus luteum can survive only 10 to 16 days, which is what defines your luteal phase. If your period comes earlier, it is irregular. A short luteal phase is a type of irregular cycle that results in low progesterone. In some women, this could be the cause of prolonged or heavy menstrual bleeding, bleeding between periods, and premenstrual syndrome.
In the week or two leading up to your period you may experience a wide variety of symptoms, known as premenstrual syndrome (PMS). PMS is characterized by a number of significant mental, physical, and behavioural changes. These changes recur in the luteal phase of a woman’s cycle, and cease soon after menstruation starts. If these changes are severe enough to disrupt quality of life and affect your normal activities of daily living, then a diagnosis of premenstrual dysphoric disorder (PMDD) is considered.
I mention PMS here because it is common, not because it is normal. This post was all about normal menstrual cycle patterns, so please be aware that PMS symptoms are not considered normal. Given their recurrent nature in the luteal phase, PMS symptoms may be caused by a hormonal imbalance of high estrogen, low progesterone, and inflammation.
When hormones are balanced, all four phases of the menstrual cycle are normal: menstruation, the follicular phase, ovulation and the luteal phase. A number of factors increase the chance of abnormal menstrual cycle patterns. Most relate to hormone production. The two main hormones that impact menstruation are estrogen and progesterone. These are the main hormones that regulate the cycle.
Next post, I’ll cover common abnormal menstrual cycle patterns or “period clues”, and what they might mean.