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LH Surge and Ovulation: When do you ovulate after an LH surge?

Welcome to the umpteenth article you’ve read about LH surge and Ovulation. Perhaps you’ve been trying to answer that ONE question that has been whizzing through your brain at supersonic speed: When do you ovulate after an LH surge?

You’ll be relieved to hear that you ovulate in about 24 to 36 hours after an LH surge! 

That simple, huh? You don’t have to read tons of text to get what you’re looking for. The answer is right there. 

But if you want to know all about the luteinizing hormone, including how to track an LH surge, then you may want to read the whole blog. 

What is Luteinizing Hormone?

Luteinizing hormone is a fertility hormone that starts your fertility window. Although your LH levels remain steady during your cycle, they seem to jump up right before you ovulate!

Now, that period when there is a sudden surge in LH is called the follicular phase. The follicles in this phase grow bigger and prepare to release an egg. 

Thanks to the high level of LH, one of these follicles releases its egg during your cycle, causing ovulation. 

There’s a critical event that happens when you ovulate. That released egg advances down your fallopian tube.

If there is a sperm nearby to fertilize it within 24 hours, it will move into your womb, where it attaches and develops into a baby. 

If this doesn’t happen, “lady red” (also known as your period) comes visiting once again. 

How long does the LH surge last?

Typically, an LH surge lasts for two days. You should note the span of your LH surge before your ovulation. This goes a long way in timing sex when you are most fertile. 

LH isn’t the only hormone that predicts when your ovulation will happen. For a fact, estrogen triggers the beginning of your fertile window. After about two days, your ovulation begins. 

When do you ovulate after an LH surge?

Most women experience their ovulation within 24 to 36 hours after an LH surge. However, once your ovulation is over, the LH falls back to its original level before you ovulate. 

Speaking of your LH level, there is a range that your LH level maintains during the follicular phase, which is from 1.9 to 14.6 IU/L.

After the surge, your body shifts to the luteal phase. Here, your LH level is between 0.7 and 12.9 IU/L.

Now, look at the exciting part. During the LH surge, your hormone ranges between 12.2 IU/L and 118.0 IU/L! 

Tracking your LH surge properly

Not only is tracking your level of luteinizing hormone essential but choosing the proper methods is too. 

Below, we will briefly explain three common ways that you can use to track your LH surges. 

  • Taking a blood test:
    Although this is the most accurate way to track your LH, it needs you to always be at the lab for tests. Generally, people who are trying to conceive or avoid pregnancy need 10-15 tests monthly. Now, imagine the stress and inconvenience it puts you through!
    If you reduce the frequency of tests then you stand a high chance of incorrectly tracking your ovulation day as it may fluctuate monthly.
    But the bright side is that this method isn’t for everyone. It’s highly recommended for people who find it challenging to ovulate or get pregnant. 
  • Using an ovulation kit:
    These kits are the right pick for home use. They work by measuring the level of LH in your pee to tell you whether you have a surge or not.
    For this method to work hitch-free, you need to record your results daily in a notepad or laptop diligently.
  • Trying Hormone Trackers:
    An efficient and seamless way to track your LH level is with a do-it-yourself hormone tracker like Inito. The Inito monitor allows you to see the values of your luteinizing hormone plus a whooping bonus of an auto-reminder to take tests.
    Inito works like a regular home pregnancy test, which can measure your LH, estrogen, and progesterone all in one test!

Ways to check if you ovulated

Asides from LH tests, you might want to try out other tests to confirm that you ovulated, like: 

  • A blood test from your doctor: Apart from the luteinizing hormone, high progesterone levels signify that ovulation actually occurred. You can take this test about a week before your next period.


  • Tracking your Basal Body Temperature (BBT): Basal body temperature is your temperature when you’re entirely resting. Taking this tempering daily at the same time will help you notice a minor increase on your ovulation day.


  • Testing for PdG: PdG is the broken-down form of progesterone. This directly means that a high level of progesterone is also a high level of PdG. 
    You can quickly test this hormone at home using a PdG testing monitor. It’s more effective if you try at about 6 to 8 days past ovulation because the hormone is highest. 


Will I always ovulate after an LH surge?

Well, it depends. Yes, a spike in your luteinizing hormone shows that you have a high chance of ovulating. However, there is still a tiny chance that you may not ovulate. This could be because of different health issues that are peculiar to people like PCOS where baseline LH levels are usually high.

Does LH surge stay high once you’re pregnant?

You may think your LH levels remain high even when you’re pregnant, considering all you have read. 

But no, it doesn’t. The LH level in your body drops immediately after your ovulation and remains low during pregnancy (less than 1.5 IU/L).

Even though LH levels fluctuate throughout a woman’s menstrual cycle, the typical range during your period is 5 – 25 IU/L


How fertility monitors can track your LH surge

These fertility monitors make sure you can quickly check and track your hormones, particularly fertility hormones in your body.  Some of them come with an app that you can download to your device.

When you have all you need, then you can start testing for your LH surge!


  • Luteinizing Hormone (LH)  is a fertility hormone that starts your fertile window.
  • Right before ovulation, your LH levels spike up.
  • This spike is called an LH surge, which lasts for two days.
  • Most women ovulate about 24 to 36 hours after an LH surge.
  • Tracking your LH level can help monitor the surge and predict when you’ll ovulate.
  • Inito Monitor helps you to measure, track and record your hormone levels to assist in your fertility journey.

Was this helpful?

  1. Oliver, R. Embryology, fertilization. In: StatPearls. StatPearls Publishing. 2021.
  2. Kerin J. Ovulation detection in the human. Clin Reprod Fertil. 
  3. Lh – clinical: luteinizing hormone (Lh), serum. Mayoclinic
  4. Kumar P, Sait SF.Luteinizing hormone and its dilemma in ovulation induction. J Hum Reprod Sci. 2011.
  5. Holesh JE, Bass AN, Lord M. Physiology, ovulation. In: StatPearls. StatPearls Publishing; 2021.

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