In today’s article, I want to answer a question I get asked all the time: How to figure out the phase of the menstrual cycle I’m in?
The four phases of the cycle
The menstrual cycle can be divided into four phases:
- menstrual phase,
- preovulatory phase,
- ovulatory phase, and
- premenstrual phase.
If you have a natural menstrual cycle (meaning if you’re not taking or using any form of hormonal birth control, pregnant, or breastfeeding), you’re somewhere on this hormonal continuum on any given day.
The “textbook” cycle — why this standard approach rarely works
Many resources on menstrual education assign specific cycle days to each phase. Something like this:
- Menstrual phase: from day 1-7 (approx.)
- Preovulatory phase: from days 7-11 (approx.)
- Ovulatory phase; from days 12-16 (approx.)
- Premenstrual phase: from days 16-28 (approx.)
⚠️ But this standard approach rarely works! ⚠️
And there are a few reasons for that:
1. Not everyone has a 28-day cycle
This is, in fact, one of the biggest myths around the cycle.
A healthy cycle is anything from 24-35 days. 28 is just the average between 24 and 35 and is used to understand the cycle in general terms. Your cycle could be shorter or longer than 28 days, and it’s OK.
What is important to know is that if it’s shorter than 24 or longer than 35 days, or if you are not ovulating, it’s a sign of an imbalance.
2. The length of each phase varies from person to person and from cycle to cycle.
If you have a regular cycle, figuring out the length of each phase will be easier for you.
However, some people have irregular cycles. Mine, for example, sometimes lasts 27 days, sometimes 33, sometimes up to 45 (this is due to PCOS). And, of course, if the cycle length varies every month, so will the phases, specifically the preovulatory phase (more on this in a moment).
3. Several factors can affect the length of the cycle.
Whether you are regular or not, you should consider that things like stress, illness, jet lag, dietary changes, etc., directly affect the length of your cycle.
This makes a lot of sense from a biological point of view. When your brain senses that you are in stress or danger, it signals your ovaries that it’s not a good time to make a baby. Consequently, ovulation is delayed for a few days or even weeks, which lengthens your cycle. It’s not exactly that your period is late but ovulation is, and in consequence, your period.
So, how to figure out the phase of the menstrual cycle I’m in?
The key is to learn to identify the ovulatory phase in your cycle.
But I’m getting ahead of myself. Let’s break it down phase by phase:
This is the easiest to identify because it’s your period! This phase starts on the first day of bleeding (a full bleeding, no spotting) and ends when your period ends.
It’s important to make a distinction between menstruation and spotting.
Some people have spotting a few days before their period. If this is your case, don’t mark it as the beginning of your new cycle; those days still belong to the premenstrual phase of your current cycle, and they’re actually a sign of a hormonal imbalance.
- If you need to wear a pad, a tampon, a menstrual cup, etc., to manage your bleeding, it’s most probably the first day of your period.
- If you can go through your day without using any menstrual care product, or if you only need a pantyliner, that’s probably premenstrual spotting.
- Premenstrual spotting also looks darker than menstrual blood; sometimes it can be brownish because the blood flows slower and oxidizes in the air.
3-7 days is considered a healthy period length. If your period is shorter or longer, it’s a sign of an imbalance you need to address.
It starts one day after your period ends and ends when your fertile window opens.
Its length can vary from one person to another and from one cycle to another. The longer (or shorter) your cycle is, the longer (or shorter) your preovulatory phase will be.
Your ovulatory phase, also called fertile window, is the time when your body is ready to make a baby. Its length is an average of 6 days.
Ovulation happens within your fertile window.
In a “textbook” 28-day cycle, ovulation would happen around day 14. But, as we said before, this is the exception, not the rule. If you have a shorter cycle, you will ovulate earlier, and if you have a longer cycle, later.
You cannot predict ovulation, but you can learn to identify when your fertility window opens and confirm if you have ovulated.
Your body shows you clear signs of when you’re fertile in your cycle, such as:
- cervical mucus,
- basal body temperature,
- the surge in LH (luteinizing hormone),
- and the cervix position.
These signs change in your cycle depending on whether you’re fertile or not. A Fertility Awareness Method can teach you to identify them.
Identifying if and when you have ovulated is essential to understanding your cycle—it helps you know the duration of your other phases and detect irregularities.
There is a lot to say about this topic. If you want to know more, check out my free webinar, “What are Fertility Awareness Methods, and how can they help me understand my cycle?“
It starts one day after you confirm ovulation and ends the day before your next period.
Compared to the preovulatory phase, the premenstrual phase has a fixed length of 12-16 days. This means that once you confirm ovulation, it will be easy to estimate the date of your next period!
If your premenstrual phase is shorter, it may be due to a progesterone deficiency; if it’s longer, it may be an early sign of pregnancy.
Then your period comes, and everything starts again 🙂
Putting everything together
- You’re in your menstrual phase when you have your period.
- You’re in your preovulatory phase if your period has ended, but you haven’t ovulated yet.
- You’re in your ovulatory phase when your fertile window is open.
- You’re in your premenstrual phase if you have confirmed ovulation, but your period hasn’t started yet.
In other words, if you identify your ovulatory and menstrual phases, the other two phases fall into place automatically, regardless of the length of your cycle.
And what about the cycle day?
Every cycle starts with your period. In other words, cycle day 1 is the first day you bleed (remember, a full bleeding, not spotting). So to know which cycle day you’re in today, check the day when your last period started and count from there.
I hope this post helps you identify where you are in your cycle. The more you pay attention, the easier it will be to know what phase of the cycle you’re in each day.
And if you’re still struggling to know or have any questions, you can always comment below or contact me on Instagram at @carlorenzana. I’d love to hear from you.
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