Written by: Dr. Amy Beckley, PhD, Founder and Inventor of the Proov test — the first and only FDA-cleared test to confirm successful ovulation at home.
Written on 7/15/20
Updated on 10/4/21
Peak fertility will come up during your Proov testing and in the Proov Insight app, so it’s important to be familiar with it.
If you’re new to the trying to conceive world, you may have quickly realized there are a lot of new terms to learn. And sometimes, slightly different terms can mean the same thing. We know — how confusing!
Today we want to break down a common term in the fertility and Proov worlds: peak fertility. This term will come up during your Proov testing and in the Proov Insight app (available on iPhone and Android), so it’s important to be familiar with it. Let’s dive in!
What is peak fertility and why is it important?
If you are trying to conceive — or even if you are just tracking your cycle to make sure all is well with your fertility and ovulation— understanding the concept of peak fertility and being able to detect it during your cycle is very important.
Its name is pretty self-explanatory: peak fertility is the period of your cycle when you are most fertile and intercourse is most likely to result in conception. You may be wondering, Wait, isn’t peak fertility the same thing as my fertile window? Sort of, but not exactly.
You see, your fertile window can last up to 5 days, which is how long sperm can survive in the female reproductive tract. Because of this, you can have intercourse up to 5 days before ovulation in order to conceive. An egg, on the other hand, can only live for about 12-24 hours after ovulation occurs.
While your entire fertile window can last 5 days, peak fertility refers to your two most fertile days. According to recent studies, your two most fertile days each cycle are the two days directly before ovulation.
The chances of successful conception after intercourse on these days is 33% and 41% respectively, compared to just 20% on the actual day of ovulation. This is the main reason why peak fertility day is so important!
How do I identify peak fertility?
You can identify peak fertility using one of the following methods:
- LH tests (also called ovulation tests), like Proov Predict
- Basal body temperature tracking
- Cervical mucus monitoring
Since Proov Predict LH tests directly measure luteinizing hormone levels and can be read directly in the Proov Insight app to take your results one step further, we’re partial to testing LH in order to identify peak fertility.
Since Proov Predict LH tests can be read and quantified directly in the Proov Insight app, we’re partial to testing LH in order to identify peak fertility.
Luteinizing hormone (LH) is the hormone that surges about 12-36 hours before ovulation and triggers the follicle to release the egg. An LH surge identifies peak fertility and that ovulation should be coming very soon.
We recommend testing your LH surge starting 18 days before the start of your next period, if your cycles are regular. For a 28-day cycle, you’d want to start testing on cycle day 10. (Don’t worry — the Proov Insight app will calculate this for you!)
If your cycles are not regular you may start testing LH as early as the day after your period is over. Remember that LH surges may be short-lived and can be pretty easy to miss. Because of this, we typically recommend testing LH levels twice a day — once in the morning and once in the evening.
Also note that some people prefer to test LH levels in second morning urine since studies show levels peak in blood between midnight and 8 am, then need a few hours to pass through urine.
Your first positive LH test signals “peak fertility,” also referred to as 0 DPP (days past peak). The next two days are the most fertile of the month and if you are trying to conceive, we recommend getting busy right away!
Lastly, we’ll mention that those with PCOS may have trouble with LH tests, as they can have elevated LH levels through their cycle. In this case, we recommend tracking peak fertility using cervical mucus monitoring. Your first day of fertile cervical mucus is considered peak fertility.
Once I observe peak fertility, what do I do next?
Once you get a positive LH test signaling peak fertility, you no longer need to continue testing LH levels. A positive LH test is a positive LH test — continuing to test does not change that!
Now that you have predicted ovulation, it’s time to confirm it! Contrary to popular belief, a positive LH test does not actually mean you’ve ovulated. In fact, it’s totally possible to get a positive LH test and not ovulate (which we see often in those with PCOS).
Luckily, our FDA cleared Proov Confirm PdG tests can help you confirm successful ovulation from the comfort of home. PdG is a urine marker of progesterone that is only present in urine after ovulation occurs and progesterone is also present in blood.
Progesterone is the hormone released by the empty follicle after ovulation and is responsible for making the uterine lining “sticky” enough to allow for the best possible chance at implantation. Without enough progesterone (and therefore PdG) during the second half of your cycle, it can be more difficult to conceive.
Progesterone is the hormone released by the empty follicle after ovulation and is responsible for making the uterine lining “sticky” enough to allow for the best possible chance at implantation.
While a single positive Proov PdG test can confirm that you did in fact ovulate, our patented PdG testing protocol recommends testing on days 7-10 past peak fertility (we told you it’s important for Proov testing!) to confirm ovulation was in fact successful. This means PdG levels remained adequately elevated for long enough during the implantation window to allow for the best possible chance at conception.
We like to see 3-4 positive PdG tests during this window (with a positive on day 10 past peak fertility) to confirm that successful ovulation did in fact occur. Successful ovulation is important because studies show that women with high levels of PdG during the mid-luteal phase (second half of your cycle) are 92% more likely to conceive and have a live birth than those with lower levels.
With the Proov Predict & Confirm kit, you can identify peak fertility and use this information to accurately time intercourse and confirm successful ovulation — all from just one, at-home hormone test kit! With personalized hormone insights, what they mean, and personalized action plans, Proov can help you reach your fertility goals faster!