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What Is Luteinizing Hormone?

Written on October 3, 2023 by Amy Harris, MPH, RN. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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Your body has more than 50 hormones working as chemical messengers to keep things working smoothly.[1] So, your health and well-being can suffer when your hormone levels aren’t where they should be. While you may not know much about it, luteinizing hormone (LH) is actually a hormonal heavy-hitter when it comes to reproductive and sexual health.

Too much or too little LH can cause many different problems, including infertility (the inability to get pregnant), changes in menstrual cycles in women, low sex drive in men, and early or delayed puberty in children. If you have questions about your reproductive health, fertility, or menstrual cycle, checking your LH levels may provide some answers. Everlywell makes it easy for you to check your LH levels from the comfort and privacy of your home with the Women’s Health Test. Keep reading to learn more about LH’s importance to your reproductive well-being.

What Is Luteinizing Hormone (LH)?

Luteinizing hormone, or LH, is an essential hormone for human reproduction. The pituitary gland makes LH. The pituitary gland is a tiny, pea-sized gland located at the base of the brain, behind your nose. The pituitary gland is sometimes called a “master gland.” It secretes multiple hormones, which, in turn, control several different glands and organs, such as your kidneys, thyroid, ovaries, and testes.[2]

Tumors and other pituitary gland disorders can impact your high or low LH levels [MedlinePlus]. Fortunately, tumors and pituitary gland disorders are relatively rare, but stress, changes in diet, lack of sleep, eating disorders, age, and other medical conditions can sometimes impact your LH levels.[4]

Do Both Genders Have Luteinizing Hormone, or Only Those Assigned Female at Birth (AFAB)?

Both genders have luteinizing hormone. LH is necessary for healthy sexual development and functioning. In children, LH levels start low in early childhood and begin to rise a couple of years before the start of puberty.[3]

In people AMAB, LH causes the testicles to make testosterone so that they can make sperm. Unlike in women, LH levels in men do not change very much across the lifespan.[3]

How Does Luteinizing Hormone Impact the Menstrual Cycle?

The timing of when and how much luteinizing hormone the pituitary gland releases can determine whether or not your menstrual cycles are regular and if you can get pregnant.[5] LH stimulates and matures ovarian follicles in the ovaries, getting them ready to “hatch” like chicken eggs or ripening berries before they are ready for picking and eating.

Ovarian follicles are tiny, fluid-filled sacs in the ovary that contain immature eggs. Over the course of a normal menstrual cycle, the egg matures. Once mature, the follicle breaks open to release the egg from the ovary for possible fertilization. LH normally rises right before ovulation.[4] It remains at this higher level for the entire second half of the menstrual cycle.[3]

Does Luteinizing Hormone Play a Role in Fertility?

Yes, it does. If you are trying to get pregnant, you want to pay attention to your LH levels. Think of LH as the person at the start of a running race who blows the starting horn or whistle — LH is responsible for kicking off your monthly ovulation cycle. If that starting whistle isn’t loud enough or comes too late, then no one knows when to start running, the race is full of confusion, runners collide, and no one wins the race.

The same is true with the menstrual cycle. Ovulation is a sensitive and intricate series of feedback loops, each depending on hormones being released at the right time and in the right amount.[5] LH deficiency can be one possible cause of infertility because it can prevent ovulation and disrupt the menstrual cycle.[6]

LH works as a team with another hormone, follicular stimulating hormone (FSH). These two chemical messengers coordinate the timing and success of ovulation.[3] Your ovaries require an LH surge to trigger them to release an egg — otherwise, you can’t get pregnant.

The second way LH impacts fertility is by supporting your ovary’s production of another hormone, progesterone. LH levels stay high for the second half of a regular menstrual cycle, telling the ovary to produce progesterone.[6]

Progesterone is essential for fertility because it helps stabilize the lining of your uterus. If sperm fertilize an LH-triggered egg, it travels down the fallopian tubes, into the uterus or womb, and implants in the womb lining. Just like a seed needs well-fertilized, rich soil to sprout and grow into a plant, a fertilized egg needs a thick and healthy womb lining to develop into an embryo. Progesterone is essential for supporting this early stage of pregnancy.[3]

Everlywell Womens Health Test CTA graphic

Is There a Test for Luteinizing Hormone Levels?

Yes, you can have the levels of LH in your blood tested with a blood draw, done at a laboratory, and ordered by a healthcare provider. When tested with several other hormones, testing your blood LH levels can be used to identify and treat[4]:

  1. Changes in menstrual cycles, such as periods that come infrequently or are very heavy
  2. The start of perimenopause — the time in midlife when those AFAB stop ovulating
  3. Infertility
  4. The time when you ovulate and are most likely to get pregnant

Another more convenient option for LH testing is Everlywell’s Women’s Health Test. This comprehensive hormone panel is appropriate for women at all stages of life. Our Women's Health test measures hormone and antibody levels to see whether your hormones are within normal ranges or if any abnormal levels may be causing symptoms that keep you from feeling like yourself. You can easily and conveniently check the levels of the following hormone and one antibody levels easily and conveniently from your own home:

  • Estradiol
  • Progesterone
  • Follicular Stimulating Hormone
  • Luteinizing Hormone
  • Cortisol
  • Thyroid Stimulating Hormone (TSH)
  • T3 (triiodothyronine)
  • Free T4 (thyroxine)
  • Testosterone
  • Thyroid peroxidase antibodies

Don’t Ovulation Predictor Kits or Tests Also Test Luteinizing Hormone?

Yes, they do. If you or a friend have been trying to get pregnant, you may have heard of ovulation predictor kits (OPK) or ovulation prediction strips. These at-home tests, sold over the counter, can test LH levels in your urine.[7]

These test results can tell you if you may be ovulating soon and how fertile you are. Because your LH levels rise three days before ovulation, testing your urine midway through your cycle can help tell when to have intercourse or have intrauterine insemination (IUI) if you are using a sperm donor.[7]

The chance of pregnancy is highest when sperm are in your fallopian tubes at the time of ovulation. So, it's ideal to have sex three to five days before ovulation (to give the sperm time to travel from the cervix to the fallopian tubes). It makes sense that you will be most fertile (i.e., have the best chances of getting pregnant) if you have sex when there is a fresh egg for sperm to fertilize.

LH predictor tests have been shown to be very accurate in predicting the LH surge and are a great tool for people to use if they are trying to get pregnant.[10] They are less effective in helping prevent pregnancy or predicting when a woman is least fertile.[8]

Find fertility, pregnancy, and postpartum products like ovulation tests and fertility supplements on our sister company’s website, Natalist.com

When Should You Think About Checking Your LH Levels?

If you were AFAB, you might want to consider testing your luteinizing hormone if[4]:

  1. Your menstrual cycles are irregular. You may have irregular periods if there are less than 21 days between them or further than 35 days apart. If you miss three periods in a row or have periods much heavier or lighter than what is normal for you, they are also considered irregular.[9]
  2. You've been unable to get pregnant after 12 months of trying and not using a birth control method.
  3. Your periods have stopped.
  4. You have other symptoms of pituitary gland disorders, such as [2-4,11]:
  • Vision changes
  • Headaches
  • Rapid-onset weight gain or weight loss
  • Fatigue
  • Weakness
  • Diabetes
  • High blood pressure
  • Leaking breastmilk when you do not have a baby or are pregnant

Learn More About Your Hormones with Everlywell

As you have probably gathered from reading this post, hormones are complicated. It can be confusing to figure out what hormonal changes might be happening in your body in response to stress, changes in diet, age, or even potentially rarer medical conditions like pituitary gland disorders.

You can begin figuring out your symptoms and your reproductive health by learning more about your hormones. Hormone tests like Everlywell’s Women’s Health Test may not give you all the answers you seek, but they can help reveal new insights about your health.

By offering you a way to measure some key hormones influencing women's overall well-being from the comfort and convenience of your own home, Everlywell helps to put control of your reproductive health at your fingertips.

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  1. Hormones. Cleveland Clinic. https://my.clevelandclinic.org/health/articles/22464-hormones. Accessed September 11, 2023.
  2. Disorders of the pituitary gland. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/disorders-of-the-pituitary-gland. Accessed September 10, 2023.
  3. Luteinizing hormone. Cleveland Clinic. https://my.clevelandclinic.org/health/body/22255-luteinizing-hormone. Accessed September 11, 2023.
  4. Luteinizing hormone (LH) level test. MedlinePlus. https://medlineplus.gov/lab-tests/luteinizing-hormone-lh-levels-test/. Accessed September 10, 2023.
  5. Saei Ghare Naz M, Rostami Dovom M, Ramezani Tehrani F. The Menstrual Disturbances in Endocrine Disorders: A Narrative Review. Int J Endocrinol Metab. 2020 Oct 14;18(4):e106694. doi: 10.5812/ijem.106694. PMID: 33613678.
  6. Di Segni N, Busnelli A, Secchi M, Cirillo F, Levi-Setti PE. Luteinizing hormone supplementation in women with hypogonadotropic hypogonadism seeking fertility care: Insights from a narrative review. Front Endocrinol (Lausanne). 2022 Aug 1;13:907249. doi: 10.3389/fendo.2022.907249. PMID: 35979440.
  7. Leiva R, Burhan U, Kyrillos E, Fehring R, McLaren R, Dalzell C, Tanguay E. Use of ovulation predictor kits as adjuncts when using fertility awareness methods (FAMs): a pilot study. J Am Board Fam Med. 2014 May-Jun;27(3):427-9. doi: 10.3122/jabfm.2014.03.130255. PMID: 24808123.
  8. Fertility Awareness-Based Methods of Family Planning. ACOG. https://www.acog.org/womens-health/faqs/fertility-awareness-based-methods-of-family-planning. Accessed September 11, 2023.
  9. Irregular periods. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/14633-abnormal-menstruation-periods. Accessed September 11, 2023.
  10. Soumpasis I, Grace B, Johnson S. Real-life insights on menstrual cycles and ovulation using big data. Hum Reprod Open. 2020 Apr 16;2020(2):hoaa011. doi: 10.1093/hropen/hoaa011. PMID: 32328534.
  11. What is the pituitary gland? UChicago Medicine. https://www.uchicagomedicine.org/conditions-services/endocrinology-metabolic-disorders/pituitary-and-neuroendocrine-disorders. Accessed September 10, 2023.
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