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The science behind the Modern Fertility Ovulation Test

The science behind the Modern Fertility Ovulation Test

7 min read

Ovulation: it's a big part of your overall reproductive health, and, of course, your fertility. When you ovulate and what’s involved might seem like a mystery, but you can demystify the process and figure out when you’re most likely ovulating with the help of the Modern Fertility Ovulation Test and App.

While no ovulation test or ovulation predictor kit can tell you for sure if you’re ovulating, ours is 99% accurate at detecting luteinizing hormone (LH) — the hormone that peaks right before ovulation. With our Ovulation Test, you can track your LH to predict your two most fertile days. With our test, you’ll get more insight than just a positive or negative result — you’ll be able to see your LH change daily and track low, high, or peak levels.

(This is key for understanding when you're in your fertile window and approaching ovulation if you’re trying to conceive — but this info can also be super valuable even if you’re not trying for kids. More on that later!)

Here, we’ll explain exactly what happens in your body during ovulation and how the Modern Fertility Ovulation Test and free app work.

What happens when you ovulate?

While understanding your ovulation patterns can give you the best chance of correctly timing sex or insemination, it can also clue you in to what's going on with your reproductive system. But what actually happens when you ovulate? Which hormones are involved and what do they do?

Ovulation separates the two phases of the menstrual cycle. Here’s a quick refresher:

  • The cycle kicks off with the follicular phase — this is when follicle-stimulating hormone (FSH) causes the ovarian follicles (which house eggs) to mature and get ready to release an egg. The maturing follicle produces estradiol (a form of estrogen), which sends a signal to the brain to release luteinizing hormone (LH).
  • Then comes ovulation. A spike in LH initiates the release of an egg from your ovary into the fallopian tube — making the hormone a great indicator of ovulation. This surge happens 24-48 hours before the egg is released, and it's this surge that's detected by an ovulation test (more on this later).
  • After ovulation is the luteal phase. The follicle that released that egg becomes the corpus luteum, which produces progesterone, a hormone that supports fetal growth.

Why should you track your ovulation with the Modern Fertility Ovulation Test Strips and free app?

If you want to get pregnant

Once you’re ovulating, things (and by "things," we mean "sperm") need to move pretty quickly. Eggs have a brief shelf life — just 12-24 hours — so sperm needs to get to the egg in that time frame in order for conception to occur. That's why it can be helpful to pinpoint your fertile window with an ovulation test and time sex or insemination accordingly.

The Modern Fertility Ovulation Test and free app can give you the hormonal info you need to find your two most fertile days and can help you predict ovulation. The way it does that is through measuring the LH in your urine — if your LH is surging, you’re likely about 24-48 hours from ovulation and have the highest chances of getting pregnant.

If you’re not planning to get pregnant

You can also use the Modern Fertility Ovulation Test to simply learn more about your menstrual cycle — and we’re in full support of getting that kind of knowledge. If you’ve recently stopped taking hormonal birth control, for example, you can use our test to reacquaint yourself with your cycle in its unadulterated form.

How does the Modern Fertility Ovulation Test Strips and free app work?

Standard ovulation tests you find at stores today are mostly threshold-based. In plain speak, what that means is they give you a “positive” or “negative” result when you pee on them.

But everyone has their own LH pattern. In fact, about 1 in 10 of us surge at a level that typically isn’t detected by standard ovulation tests (so you may see a negative result even if you’re approaching ovulation).

We worked closely with our medical advisory board to create a semi-quantitative strip ovulation test that gives you more nuanced insight into your LH levels. Our test detects your LH at low, high, or peak levels to help you predict your LH surge – even if you have irregular cycles. We also have a free app to help you more easily track your unique LH surge and better predict your fertile window.

Here’s how it works:

  • If there's LH in your urine, this test will find it. That LH attaches to LH antibodies in the test and causes a test line to show up — indicating your LH level.
  • When you take the test, your test line will darken according to the levels of LH in your pee. You can then match the shade of the test line to its corresponding LH concentration (displayed on the test wrapper) and find out whether your level is low, high, or peak. (These strips are like the mood rings of ovulation.)
  • If you’re using our free app, you can scan your test with your phone’s camera to log the result. The app will track your numerical LH levels and predict your fertile window.

Here’s where the magic really starts happening: If you track your LH levels over time (using the log provided with the test or with our free app), you can get even more in sync with your unique LH pattern. Using the log, you can visualize when you’re hitting your LH surge — and not just go by the average surge level that the majority of people with ovaries experience.

Preview of how the Modern Fertility App works.

Importantly, you don’t need to have regular cycles to take the test. Since you’re testing based on your unique LH pattern, you can still detect your surge if your cycles are irregular. That said, it’s always a good idea to check in with your doctor if your cycles are irregular — especially if they’re under 21 days, over 36 days, or if you’ve been diagnosed with a condition like polycystic ovary syndrome (PCOS). Talking with your doctor can help you figure out when (or if) you’re ovulating each cycle.

How do you take the test and read the test strips?

Besides peeing in a designated area (we’re sure that doesn’t need to be said, but it can’t hurt to clarify!), what else do you need to know about taking the test? We've got the details you need.

  1. Test 19 days before the start of your period. To figure out when that is, you’ll need to determine your cycle length and subtract 19 days from that number. (It might take you a whole cycle to count the length, and that’s totally okay.)
  2. Test first thing in the morning, since that's when your urine is the most concentrated. You can test again in the afternoon or evening, but don't drink a lot of liquids beforehand — it will dilute your urine and may skew the results.
  3. Save the wrapper once you open the test — it has a chart you'll need later.
  4. Pee into a cup, and then insert the absorbent end of the strip up until the “MAX”line (but not past it).
  5. Be sure to lay the test down so that it's flat, and read it after 5 minutes. If you wait 10 minutes, the results will be invalid.
  6. Use the test wrapper to check your test result line against the shades on the chart to find your LH concentration. (See image above for reference)
  7. You can also use it with the Modern Fertility App. The *free* Modern Fertility App works with our Ovulation Test to help you pinpoint your 2 most fertile days. It uses your camera to automatically scan and log your test so you can better predict your fertile window. Think of it like having a tiny fertility scientist in your pocket.
  8. Don't stop at testing just once. We recommend testing for 11 days to get a sense of your LH pattern and when it typically surges.

It’s time to modernize reproductive health

Yes, we’re hormone nerds — and we’re proud of it. Our mission is to make personalized fertility information more accessible. In addition to our Ovulation Test, we also offer two additional at-home tests:

  • The Modern Fertility Pregnancy Test, which is just as accurate from the day of your missed period as leading pregnancy tests — and is also more affordable. It also works like magic with our app.
  • The Modern Fertility Hormone Test, which measures the same fertility hormones that a doctor would test in a fertility clinic (for a fraction of the price) and helps you understand how your fertility is changing over time. Our test gives you insight into the number of eggs you have and can help you identify red-flag issues — like PCOS or thyroid conditions — that could affect your reproductive health down the line.

We believe that understanding your hormones is the key to understanding your fertility and reproductive health. Our at-home tests and free app give you the info you need about your body to get proactive about all things fertility.

Did you like this article?

Dr. Sharon Briggs, PhD

Sharon leads Clinical Product and Research at Modern Fertility. She's a craft beer-loving, soccer-playing, cookie-baking scientist who completed her PhD in Genetics at Stanford University.

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