How to predict the arrival of your next period

Or what if you have a “short” menstrual cycle (one that spans fewer than 28 days)?

Or what if you have a “long” menstrual cycle (one that spans more than 28 days)?

Or what if you have a menstrual cycle that varies in length from month to month (for example, 28 days one cycle, then 31 the next, then 25 the next)?

As long as you have a healthy menstrual cycle (meaning no hormone disorders or missed ovulations), you can still use Hormonology to find out what your mood, energy and more will be every day of your cycle.

And, also useful, you can always know when you’ll get your period–regardless of how long your cycle is. That’s right–no more guessing, no more surprises.

How? Math. Very, very simple math.

The female menstrual cycle formula

The reason you can use Hormonology and predict when your next period will arrive regardless of how many days are in your cycle is because of the way your menstrual cycle is naturally set up:

The first “half” of your cycle–the follicular phase, which spans the first day of your period through ovulation–is the only part of your cycle that varies in length.

The second “half” of your cycle–the luteal phase, which spans the day after ovulation through the day before your next period–is generally a stable 14 days. That’s because once ovulation occurs, an inner clock inside your body begins to tick down either to your period or pregnancy. If you didn’t get pregnant, then the clock stops at 14 days, and you get your period.

This means that if you have a 28-day cycle, it’s because the first half of your cycle was 14 days.

If you have a shorter cycle, it’s because the first half of your cycle was shorter than 14 days. For example, if your cycle was 26 days long, the first half of your cycle was just 12 days.

If you have a longer cycle, it’s because the first half of your cycle was longer than 14 days. For example, if your cycle was 30 days long, the first half of your cycle went on for 16 days.

So, the key is to pinpoint when you ovulate (I’ll get to how you do that in a minute), then count down to 14 days. That’s when you’ll get your next period.

One caveat: Some women have luteal phases that are slightly shorter or longer, such as 13 days or 15 days. But, typically, this phase is still a consistent set number of days, so track your cycle to determine how long your luteal phase is if it’s not 14.

Adapting your cycle to Hormonology

Now that you know how your menstrual cycle works, here’s why Hormonology adapts to every cycle length:

Hormonology shows you how your hormones impact you every day of your cycle. It shows you this on a daily basis and it also breaks your cycle up into four easy chunks–Week 1, Week 2, Week 3 and Week 4.

Week 1 and Week 2 are the first half of your cycle–from the first day of your period through ovulation. On these days, your hormones are doing the same thing–estrogen is climbing higher and higher. So, no matter how long or short this first half of your cycle is, you’re really experiencing the same hormonal effects. They just get more and more intense as you approach ovulation, for instance, your mood, energy and libido steadily increase.

Week 3 and Week 4 are the second half of your cycle–14 days long with Week 3 lasting 8 days and Week 4 lasting 6 days. The hormone fluctuations going on during this phase of your cycle are a bit more complex: Estrogen falls, then rises, then falls again. And progesterone rises and falls. But, the most important part is that for the sake of predicting your period, you’ve got 14 days in this cycle phase. (If your luteal phase is slightly shorter or longer, you’ll still follow the same hormonal up-and-down pattern.)

Detecting ovulation

You may have thought that detecting ovulation was only important for getting pregnant or avoiding pregnancy. But, as you can see, ovulation is an important signpost that tells you where you are in your cycle.

So, how can you tell when you’ve ovulated?

There are a few physical symptoms you can look for, which include feeling pain (called “mittelschmerz”) in either ovary and seeing egg white-like vaginal fluid. However, I prefer to use ovulation detection tools since they’re more reliable. These include:

• Basal thermometer: You use this sensitive thermometer to take your temperature when you wake up, but before you get out of bed to detect a subtle rise in your body temperature of about .5 to 1 degree that occurs at ovulation. This change happens due to rising progesterone, which elevates core body temperature.
• Ovulation test strips: These easy-to-use test strips measure the level of luteinizing hormone (LH) that peaks about 24 to 36 hours before ovulation. Simply pass them through your urine to find out your LH level.
• Ovuation mini-microscope: This lipstick-sized reusable miniature microscope measures the amount of salt in your saliva, which peaks shortly after ovulation due to spiking estrogen. Dab a little spit on the microscope lens, let it dry, then look through the viewfinder. If you see fern-like patterns, your salt level is peaking, so you’ve ovulated the day before.

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Your egg is the crystal ball

Now that you know how to detect ovulation and that ovulating means there are 14 days left to your cycle (or the number of days typically in your luteal phase), you’ll always be able to accurately predict when your next period will be arriving.

As a result, you can use Hormonology to find out how the ups and downs of your hormones will be impacting your moods, energy and more so you can predict virtually every aspect of your day and more easily plan your life–no matter what length your cycle is or if its length varies.

To find out how your hormones impact you every day of your menstrual, pick up my book, 28 Days: What Your Cycle Reveals About Your Moods, Health & Potential, which is available at Amazon in ebook and paperback.