Luteinizing Hormone Test and Its Importance in Fertility

The doctor advises an LH blood test mainly as a routine part of an infertility workup. Luteinizing hormone is necessary for the proper functioning of reproductive organs and sexual development.

In women, it is involved in bodily activities like:

• Puberty: The high level of LH can result in early puberty, and the low levels of LH can slow down puberty.
• Menstrual cycle: Along with Follicle Stimulating Hormone (FSH), LH works to regulate and control the menstrual cycle [2].
• Ovulation: Increased levels of LH stimulates ovaries to release eggs, known as ovulation.

In the case of men, it plays a role in:

• Production of testosterone: LH causes the release of testosterone by stimulating Leydig cells of testes.
• Production of sperm: The released testosterone then starts sperm production.
• Puberty: If the LH level is low, the puberty in boys is delayed, and he attains puberty earlier than the expected time if the LH level is high.

As discussed earlier, the LH hormone is secreted from the pituitary gland. In females, the LH hormone helps in releasing eggs from the ovaries, and in males, it triggers the release of testosterone from testes. The LH blood test helps in identifying the cause of infertility in both men and women. Tracking the LH level in women tells about the days when the chances of natural conception are highest (ovulation days). The LH test also helps in diagnosing pituitary gland disorder.

The doctors may recommend LH testing in females if they have [3]-

1. Fertility issues: If the women are not able to get pregnant after trying for more than 12 months.
2. To track ovulation: If you are planning to conceive and want to know your ovulation timing and fertile days, your doctor may recommend an LH test.
3. To identify the reasons for irregular menstruation.
4. To confirm the beginning of menopause (LH rises when you enter your menopause).

In males, the doctor will ask to get LH testing done for issues such as-

1. To identify the cause of infertility.
2. To find the reason for low sex drive.
3. To find the reason for low sperm count.

Additionally, the doctor may also prescribe the LH test in children to know the reason for early or slow puberty. Early puberty is due to high LH levels, and postponed puberty is due to low LH levels.

The LH level varies depending on gender, age, and health conditions. Let's understand the normal value of LH and what does the high and low level of luteinizing hormone shows,

LH levels in women

The normal LH range varies according to the menstrual cycle in women.

• In your follicular phase of the menstrual cycle: 1.68 to 15 IU/L
• At your mid-menstrual cycle peak: 21.9 to 56.6 IU/L
• In your luteal phase: 0.61 to 16.3 IU/L

The LH level in pregnant women is less than 1.5 IU/L, and during menopause, the LH level ranges from 14.2 to 52.3 IU/L [4]

Abnormally high levels of LH in women, when they are not ovulating, indicates they are reaching menopause. It may also mean that they might have PCOD (Polycystic ovarian syndrome) or pituitary dysfunction.

Women with a low level of LH hormone are not able to ovulate and hence may find it tough to conceive naturally. Low LH levels may also mean that they have anorexia (a type of eating disorder), pituitary gland malfunction, are under stress, or suffering from malnourishment.

LH levels in men

The normal range of LH in adult males ranges from 1.24 IU/L to 7.8 IU/L. A high level of LH in men means that the testes are not able to produce testosterone. It may be due to surgery or an infection like mumps, exposure to radiation, cancer treatment, genetic conditions, or injury. Whereas, the low level of LH means pituitary gland dysfunction causing low testosterone production.

As the test result may vary slightly from one lab to the other, consult your doctor with your test results.

LH blood test is done to measure the amount of LH in your blood. If you are trying to become pregnant, your doctor might want you to get an LH (Luteinizing Hormone) test several times to pinpoint when your body releases an egg, which is called the ovulation process. Ovulation occurs approximately 10-12 hours after the LH level is at a peak. [5] The amount of LH in your blood increases with ovulation. Your doctor will take the LH test on the 3rd day of your menstrual cycle along with FSH testing to know about the ovarian function.

The whole process of blood collection will take only five to ten minutes, and you might feel a poking or stinging sensation at the time of prick, and the sore feeling of the site will soon fade away. Certain medicines may affect the LH blood test results, so your doctor will ask you to stop taking birth control pills for about four weeks before undergoing LH testing. If you had any recent tests in the past seven days like a thyroid test or bone scan, you should tell your doctor about that, as it can affect your LH test result.

If you are planning to conceive and want to know your ovulation days, you can use the ovulation predictor kits (OPK), which measures the LH surge during your menstrual cycle. The LH surge is responsible for the release of eggs from the ovary (also known as ovulation).

A high level of luteinizing hormone is associated with infertility as it impacts the reproductive system. Abnormally high level of LH in women suggests polycystic ovarian disease (PCOD) that may cause problems in getting pregnant.

Insufficient or low levels of LH will limit the production of sperm or the ovulation process, which may cause infertility in males and females. Women with low levels of LH are unable to ovulate and will not have menstruation. Due to their inability to ovulate (release of eggs from the ovaries), they will have fertility issues. After looking at fertility test results along with LH blood tests, the fertility expert will decide on the best treatment most suitable for the couple.

As we said in the previous section, abnormally high and low LH levels may cause infertility. In such cases, your doctor may suggest fertility treatments such as,

1. Medication - Your doctor may prescribe fertility medicines and injections to stimulate your ovaries to produce eggs. Sometimes, fertility medicines alone may not result in ovulation or pregnancy. Artificial reproductive methods of pregnancy are used in such cases.
2. IVF (In vitro fertilization) - The doctor may suggest In Vitro Fertilization if the fertility medicines are not working. During IVF, a woman's eggs are retrieved and fertilized with male sperm in a lab. The embryo that is formed, after 5 to 7 days of fertilization, is transferred into the woman's uterus. IVF is the best option to have a baby if you have PCOS.
3. Embryo Freezing - Your doctor may also suggest you freeze any additional embryos for future use. It is known as cryopreservation or egg freezing and helps to plan for IVF again, if necessary.
4. IVF With Donor Eggs For Ovarian Failure - If you have problems with ovarian failure, where your ovaries cannot produce eggs at all, then your doctor may suggest IVF treatment using donor eggs that can help to achieve pregnancy.

You should always think and decide after talking to the doctor about IVF, as several other factors can affect the success of IVF.