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

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It’s no secret that there lies an important relationship between LH surge and ovulation. 

We also know that ONE question that whizzes through the heads of many women around this subject: How long after LH surge do you ovulate? 

First off, let’s understand how LH surge is vital in the process of ovulation. Driven by hormonal changes in the body, an LH surge is what triggers ovulation, causing the ovary to release an egg for fertilization. 

So now you know that a rise in LH levels is where the possibility of a pregnancy begins! 

This article is your one-stop destination for all you need to know about the luteinizing hormone, what its significance is to your cycle, and how you can track this hormonal surge

What is Luteinizing Hormone?

Luteinizing hormone (LH) is a fertility hormone that kick-starts your ovulation. Produced in the anterior pituitary gland, LH works in tandem with the ovaries and its peak coincides with your fertile window. 

A fertile window lasts 6 days – 4 days before ovulation, the day of ovulation, and a day after ovulation. 

LH Hormone Chart

When understanding how LH works, you must know that its levels remain steady during your cycle and for the most part of every month. 

They however jump up right before you ovulate. The period when there is a sudden surge in LH is the follicular phase of your menstrual cycle. 

The follicular phase lasts between the first day of menstruation and the day of ovulation.
During this phase, the ovarian follicles, which contain the egg, grow bigger, and the egg matures for release.  

Thanks to the high level of LH, one of these follicles releases the mature egg during your cycle. This is what causes ovulation. That released egg advances down your fallopian tube for fertilization.

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

How long does the LH surge last?

long does the LH surge last

Typically, an LH surge lasts for two days, between 24 and 36 hours. It is best to note the span of your LH surge before ovulation. 

That will help you in knowing when you are most fertile, and accordingly, time when you should have sex in case you are aiming for pregnancy.  

LH isn’t the only hormone that predicts when your ovulation will happen. Follicles in the ovary secrete estrogen, which then leads to a release of LH from the pituitary gland. This then triggers ovulation. 

When do you ovulate after an LH surge?

Most women experience their ovulation within 24 to 36 hours after an LH surge. It is unlikely that you will get an LH surge and ovulation same day, since the hormone peak precedes the release of the egg from the ovary.

Does LH drop after ovulation?

Yes, it does. Once your ovulation is over, the LH falls back to its baseline level from before your ovulation period.

So you must now be wondering, what should my LH levels be when ovulating?

Period Phase

LH Level

Follicular Phase

1.9 – 14.6 IU/L

Luteal Phase

0.7 – 12.9 IU/L

LH Surge

12.2 – 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.

Method of ovulation test
  • Taking a blood test:
    Although this is the most accurate way to track your LH, many women find it to be a bit cumbersome. After all, who will find it convenient to visit the lab for tests every month?

    Generally, people who are trying to conceive 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 don’t stress!
    It is widely accepted that a blood test to track LH surge is not a method for  everyone. So there is no pressure to take this route. However, it is highly recommended for people who find it challenging to ovulate or get pregnant. 

  • Using an ovulation kit:
    Ovulation kits are the right pick for home use – and convenient too. They work by measuring the level of LH in your urine  to tell you whether you are going through  a surge or not.

    For this method to work hitch-free, you need to record your results daily in a notepad or laptop diligently. 
  • Fertility Monitors:
    An efficient and seamless way to track your LH level is with a do-it-yourself fertility monitor. 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 FSH, LH, estrogen, and progesterone metabolite PdG all in one test!
LH Hormone Chart

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 LH, 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. Progesterone starts rising right after ovulation and is the highest at 6 to 8 days past ovulation. Test daily to pick the rise in Progesterone metabolite-PdG levels. If your PdG levels rise earlier than 6 days, Inito can measure it easily due to its high sensitivity.
    Read More: Key Things To Know About Progesterone Tests

  • Cervical mucus: One of the easiest ways to track your ovulation is noticing changes in your cervical mucus. If the discharge turns slippery and wet, resembling the consistency of egg whites, know that your ovulation date is near. To get the low-down on cervical mucus, head here. 

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 may have read or heard. 

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. 

Does an LH surge always mean ovulation?

For women, a surge in LH levels almost always indicates the onset of ovulation. However, elevated levels of LH have also been noted in women experiencing polycystic ovary syndrome (PCOS), a common hormonal disorder that involves an increased production of androgens in the body. 

No ovulation

High LH levels are also present in women going through menopause. However, if you are in your reproductive years and track to see that your LH levels are constantly on the higher end, then you should consider making a visit to the doctor. 

LH levels away from the baseline all the time may indicate an underlying health condition or disorder like gonadal dysgenesis. 

Can there be an LH surge but no ovulation?

This can happen with a condition called Luteinized Unruptured Follicle Syndrome (LUFS), where the LH rises without the ovary releasing an egg.

A case of LUFS, apart from ovulation failure, can also sometimes point towards infertility. It is best to consult your doctors if you notice any erratic changes while tracking LH. 

Anovulation charts


  • 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.
  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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