How to Calculate Menstrual Cycles: Taking The Mystery Out of the Equation

how to calculate menstrual cycleI think one of the worst things a woman can hear is that a “textbook cycle” lasts 28 days, or that a “textbook period” lasts between 3 and 5 days.  Usually, that’s because by the time you are searching for information on your cycle, you are on something like day 40, and you are concerned that there is something wrong.  So I want to begin by saying that everything is relative, everything depends on the individual, and there is absolutely such a thing as irregular cycles.  Let’s think about this in terms of another common average – the average body temperature of 98.6.  All that means is that most people will hover around that point, and be perfectly healthy.  However, if you take your temperature every day, and find that you happen to hover around 96.6, then coming up with 98.6 one day actually means you have a slight fever.

I actually bring up temperature not just as an example, but also because it is a useful tool in tracking your cycle.  Understanding your own menstrual cycle is important for a number of reasons.  Sudden irregularities can signify that something may be wrong, so knowing your tendencies can help you catch those potential problems early.  It goes without saying that whether you are trying for a pregnancy (or trying to avoid one), knowing where you are in your cycle is of the utmost importance.  Let’s take a look at a few ways you can track your cycle.

Where Do I Even Begin?

There is a good bit of confusion surrounding “Day 1” of your cycle.  Many women have been told that the first day of their cycle is the day their period ends.  Well, if you are like many other women, you know that determining that moment is anything but an exact science.  If you tend to stop and start, or if you tend to spot for a few days at the end, how on Earth are you supposed to know when you stopped?

In reality, many women have been working off a bad piece of starting information.  Many times, people mistakenly use the terms “period”, “cycle” and “bleeding” interchangeably, and that leads to a lot of confusion.  “When your period ends”, if actually better defined as “When your prior cycle ends” – so oddly enough that means you should actually begin counting on the day your period begins.  In other words, the day you start to bleed is day 1 of a new cycle.  If you spot for a few days beforehand, this is normal too.  The first day you see red blood is considered the true beginning of your menstrual period, so make a note of that.

What Exactly Am I Tracking, Here?

how to calculate menstrual cycleA few things, actually.  Over the course of several months, you will begin to see an average forming.  If you have two cycles that lasted 34 days, and two that lasted 37 days, and one that lasted 35, when you do a little math, it tells you that your average cycle length is between 35 and 36 days long.  If you begin to see changes to those numbers that seem very out of the ordinary – for instance a cycle length of only 20 days, or one of 48 days – then you have a tip off that something may be a little off.  Call your doctor to discuss the issue if you are concerned.

Occasional irregular periods do happen, and sometimes for no reason at all.  If you are young, and have just begun getting your period, you are more likely to have some irregular cycles for a while, until your body finds its rhythm.  Certain medications can sometimes affect your periods too.  It’s a good idea to have a record of your cycles, both for your own information, and to share with your doctor.

Another reason many women track their cycles is to plan for, or avoid a pregnancy.  More on that below.

How Do I Track Ovulation?

how to calculate menstrual cycleOvulation is just a fancy term for when your body releases a mature egg cell from your ovaries.  In other words, this is the time when you are most fertile, and most likely to become pregnant, if you have unprotected intercourse.  This tends to happen around mid cycle, so for many women that means somewhere between day 11 – 21.  Bear in mind that it can happen at any time, especially of your cycles are irregular, and that some cycles may fail to produce an egg cell altogether.

There are a few physical signs to look for when trying to determine if you are ovulating.  First off, the cervical mucous (the substance you sometimes see on toilet paper after using the bathroom) will become clear and stretchy.  Many people refer to this as “egg white” due to the striking resemblance.  When you see this, you are very likely going to ovulate within a day or two.  This fluid is secreted by your body in order to make fertilization easier.  If you are trying to become pregnant, seeing that “egg white” means it’s a good time to schedule a date with your partner.  If you are trying to avoid a pregnancy, maybe rent a movie that night instead.

Another means of tracking ovulation is to use your basal body temperature (BBT).  This is accomplished by taking your temperature every morning, before you even get out of bed.  This will give you a reading of a slightly lower temperature on the days before you ovulated (Averaging around 97.2), and then a rise in temperature which lasts several days (98.6, for instance).  It is important to note that tracking your temperature can only tell you if you have already ovulated, and won’t give you any warning that you are about to do so.  That is why temperature tracking is best used along with other methods.

Keeping track of your cycles is good for your health awareness, your peace of mind, and even just for letting you know when it might be a good idea to keep some tampons in your purse.  Udemy has a great, overall course called “Biohacking Your Menstrual Cycle” which can give you even more information.