High and Peak Fertility: How Can You Tell When You’re Most Fertile?

High and Peak Fertility: How Can You Tell When You’re Most Fertile?

Published by Eilis Olson


If you’ve started your fertility journey or you’re thinking about it, you’ve probably heard of peak fertility and high fertility.

Peak fertility is what it sounds like. It’s the point in your cycle when you’re most likely to get pregnant. High fertility is right before peak fertility and marks the beginning of your fertile phase¹.

Everyone’s cycle is different and it can be difficult to determine when you’re most fertile if your cycle isn’t regular.

There are also many different factors that can affect your fertility.

At Hera Fertility, our personalized intake process helps us see the big picture, and the small details, when it comes to you and your fertility.

We want you to be equipped with the right information to make the best decisions for yourself and your family. 

So here’s what you need to know to increase your chances of getting pregnant – whether your cycle is normal or not.

The menstrual cycle and fertility

The typical menstrual cycle lasts for twenty-eight days. But don’t worry if this isn’t the case for you. It doesn’t necessarily mean you won’t be able to track your cycle. 

Your cycle is split up into two phases.

  • The Follicular Phase.
  • The Luteal Phase.

The first phase, also known as the proliferative phase, lasts from day one to day fourteen of a normal cycle². The second phase, also called the secretory phase, is from day fourteen to day twenty-eight, the last day of a normal cycle.

A lot of people have misconceptions about when it’s possible to get pregnant during their cycle and the answer is: it depends.

It’s important to note that while twenty-eight days is considered “normal”, many women have cycles that are slightly shorter or longer.

This doesn’t always signal that you have poor menstrual health and you won’t be able to get pregnant.

Plus, although it’s unlikely, it’s possible for conception to occur outside of the fertile window because sperm can survive for several days and ovulation timing can differ.

But it’s most likely you’ll conceive when you have intercourse in the fertile window, which consists of the five or six days before ovulation and the first day you start ovulating.

Peak fertility and high fertility occur during this time in your cycle. 

The idea that you absolutely can’t get pregnant outside of this window is a common myth. It can be hard to determine exactly when you’re ovulating, but there are ways to track ovulation that can give you a good idea.

High and peak fertility during ovulation

There are several ways to track your ovulation and detect your high and peak fertility. 

High fertility occurs at the beginning of the fertile window. It’s indicated by a surge in estrone-3-glucuronide. Peak fertility is marked by a surge in the luteinizing hormone (LH), which also signals ovulation. 

So high fertility typically occurs in the five days leading up to ovulation, while peak fertility is the day before you ovulate and sometimes the day you ovulate.

But of course, this is assuming a normal twenty-eight-day cycle where you ovulate on day fourteen.

This is why we now have better ways of tracking our cycles than the old calendar method.

One study observed participants tracking their cervical mucus or detecting hormonal changes with an electronic fertility monitor. Out of the 124 participants in the study, there were fifty-nine confirmed pregnancies³.

Can you guess how many pregnancies resulted from intercourse on high or peak fertility days?


The results from this study were consistent with other studies on the efficacy of intercourse within the fertile window.

So while you can get pregnant outside of your fertile window, your high fertility and peak fertility days are the best times to try to conceive.

Methods of tracking ovulation and fertility

We recently shared a blog that goes into detail about the different options for ovulation tracking, which include:

  • Basal body temperature tracking.
  • Cervical mucus tracking.
  • Ovulation predictor kits.
  • Fertility tracking apps.

Tracking your cycle can help you identify patterns and find out when your high and peak fertility days occur.

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Cervical mucus tracking for high and peak fertility

When your cervical mucus is slightly moist, thick, white, and there’s hardly any at all, you can assume it’s “low” fertile mucus.

High fertile mucus is wetter, thinner, cloudy, and doesn’t hold its shape as much. 

Your peak fertility mucus is:

  • Slippery.
  • Thin.
  • Clear.
  • Stretchy.

And there’s a lot more of it.

You might be surprised that cervical mucus tracking is pretty accurate and easy to follow. 

But you might not be able to determine your peak fertility by tracking your cervical mucus if you have continuous cervical fluid or another menstrual disorder⁴.

If you have a relatively regular cycle, there are other ways you can make sure you’re taking advantage of your peak fertility. 

Basal body temperature tracking and peak fertility 

We go over this simple method more in our blog on ovulation tracking techniques.

It involves taking your temperature when you’re in a state of total rest. 

For best results, take your temperature at the same time every day.

When you see a 0.5 to one-degree increase in your basal body temperature, that can be a sign you’re ovulating.

So if you determine a regular pattern through your body temperature, you can identify your peak fertility days based on your ovulation timing. 

But keep in mind that like all other methods, basal body temperature tracking isn’t 100% reliable. Your temperature can rise for many different reasons.

What if your periods are irregular?

If you’ve been tracking your cycle for at least six months and yours isn’t a normal twenty-eight-days, you have a few options.

If your cycle length is less or more than twenty-eight days but tends to be about the same length every month, you can still use the methods above to track ovulation. You’ll likely be able to determine your high and peak fertility days. 

If your cycle looks different every month, you can use an ovulation predictor kit to detect surges in LH⁵.

You’ll have to test more often since your ovulation day might change from month to month.

However, you might not ovulate if you have an underlying menstrual disorder. If you have irregular periods or no period at all, there’s a chance you’re not ovulating⁶.

In either of these cases, working with a fertility specialist is a step in the right direction if you want to get pregnant. 

What to do next if you’re struggling to conceive

There are a lot of factors that can impact fertility.

So if you’re not able to get pregnant by tracking your ovulation and having intercourse on your high and peak fertility days, there might be something else going on. 

A few of the factors that can impact fertility negatively are:

  • Lack of exercise.
  • Irregular sleep or lack of sleep.
  • Poor diet. 
  • High levels of stress. 
  • Certain medications.
  • Environmental exposures. 

These can contribute to both female and male infertility⁷.

The fertility journey isn’t easy for everyone. Fertility is complicated and sometimes treatment is needed to help your body prepare for your baby.

If you’ve been struggling to get pregnant for a while, get in touch with our fertility expert.

We understand that fertility looks different for each of us. Our virtual fertility services involve several steps to help us get to know you and your unique situation. From there, we come up with a personalized treatment plan. 

You’re not alone.

Reach out and book a call if you’re ready to take control of your fertility journey.

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