The LH hormone: what is it and what does it do?

The LH hormone, also known as luteinizing hormone, plays a major role in the menstrual cycle, also known as the hormonal cycle. Its main function is to trigger ovulation . This article explains everything LH does in a woman's body.

The LH hormone is produced in the pituitary gland, a hormone-producing gland in the brain. Hormones can be seen as the communication channel between the brain and the reproductive organs.

Starting at puberty, the body begins producing LH. This coincides with sexual development and the associated changes in the body.

In women, the LH hormone triggers ovulation. This is the time in the cycle when a woman is most fertile, meaning an egg is ready to be fertilized.

LH is inextricably linked to the entire female hormonal cycle. The following hormones are present in the hormonal cycle: FSH, LH, estrogen, and progesterone. During the cycle, the levels of these hormones fluctuate, triggering changes.

In short, the hormone cycle goes like this:

• Egg development - Under the influence of the hormone FSH, multiple follicles develop in both ovaries. These follicles, in turn, release estrogen. This makes the cervix more suitable for sperm.
• Complete development of one egg cell - Only one follicle fully develops each cycle. When this happens, significantly more estrogen is released.
• The ovulation - This estrogen surge is recognized by the pituitary gland, which then releases the hormone LH. The follicle bursts, and ovulation occurs. The egg then emerges from the follicle into the ovary and travels to the fallopian tube.
• Journey to the Womb - The egg travels through the fallopian tube to the uterus. The empty follicle produces the hormone progesterone. Progesterone and estrogen prepare the uterine lining for a potential pregnancy and inhibit the hormones that cause more eggs to develop.
• Menstruation - When fertilization hasn't occurred, estrogen levels drop. You then begin menstruating, and the cycle begins again.

LH levels are low throughout the cycle, except around ovulation. Then they suddenly rise sharply. This is also called the LH surge. The period during which this LH surge occurs is called the luteal phase. This is when you are most fertile.

Many women want to know when this moment is, because they want to get pregnant. An ovulation test measures the amount of LH in the urine. A positive LH test indicates ovulation will occur within one or two days.

The test works like a pregnancy test, often in the form of a strip. You take the test by collecting a sample of urine with the strip. Lines then appear, indicating whether or not ovulation is imminent.

Because LH levels vary significantly throughout the cycle, it's difficult to draw conclusions about whether LH levels are low or high. The hormone concentration is low around menstruation, while it's high during ovulation. However, there are several reasons why LH concentrations can be higher or lower than during a normal menstrual cycle.

A major cause of elevated LH levels is menopause. This is because during menopause, the ovaries no longer function and therefore no longer receive signals from the LH hormone, causing levels to remain elevated.

During pregnancy, LH levels remain low. This is logical, as ovulation isn't necessary during pregnancy. Even after pregnancy, hormones can remain unbalanced for a while.

When using the contraceptive pill, LH hormone levels are low. This isn't surprising, as ovulation doesn't occur while on the pill. The pill actually prevents ovulation, preventing pregnancy.

When the ovaries don't function properly, the messages from the brain, in the form of the LH hormone, aren't received properly. LH levels then remain elevated. Ovarian dysfunction can have several causes.

• Underdeveloped ovaries
• Genetic abnormality, such as Turner syndrome
• Chemotherapy
• Autoimmune diseases
• A tumor in the ovary
• PCOS

When the pituitary gland isn't functioning properly, it sometimes can't produce LH. As a result, levels of this hormone remain low. There's a good chance that ovulation won't occur.

A high or low LH level has similar symptoms. These symptoms are more common with hormonal imbalances, such as progesterone or estrogen. The similarity of these symptoms is no coincidence, as hormones interact as a system and are therefore difficult to separate.

Symptoms of LH hormone imbalance:

• Irregular menstruation
• Reduced fertility (difficulty becoming pregnant)
• Hot flashes
• Night sweats

Both a low LH level and an excess, whether caused by natural or medical conditions, can indicate a hormonal imbalance. Restoring your hormones to a more balanced state can be achieved through various lifestyle changes.

Tips for hormonal balance:

• Power supply - A healthy diet is crucial for maintaining hormone balance. Eat a healthy, varied diet and drink plenty of water. Also, keep an eye on your macronutrient intake, such as protein and healthy fats.
• Healthy weight - Both being underweight and overweight can cause hormonal imbalances. Therefore, try to maintain a healthy weight.
• Exercise in moderation - Excessive exercise can cause hormonal problems or even completely disrupt your cycle. Exercise is healthy, including for your hormones, but do it in moderation.
• Reduce stress - Stress and stress hormones throw your hormones out of balance. Therefore, try to reduce stress.
• Get enough sleep - Take a closer look at your sleeping habits and try to improve your sleep hygiene, for example.