The path to family planning can be filled with questions about your fertility and reproductive health. From lifestyle habits to hormone levels, many factors come into play when assessing fertility. One hormone that plays a role in ovulation and fertility is luteinizing hormone (LH). But what exactly is LH, and can LH testing provide useful information for your reproductive journey?
What is LH?
LH is a reproductive hormone produced by the pituitary gland that serves different key roles in women and men. In women, LH (along with other hormones like follicle-stimulating hormone [FSH] and estrogen) supports ovulation, which is the release of a mature egg from the ovaries. Specifically, FSH and estrogen are critical in follicle development and maturation leading up to ovulation, while LH triggers the ovulation process, causing a follicle on the ovary wall to rupture and release an egg into the fallopian tube.
LH also promotes the production of other hormones involved in the menstrual cycle and fertility. In the luteal phase after ovulation, LH helps stimulate the empty follicle to transform into the corpus luteum, a structure in the ovary that forms each month and produces progesterone. Progesterone helps thicken and maintain the uterine lining to support a pregnancy.
In men, LH plays a role in stimulating the production of testosterone, the male sex hormone important for sperm production and reproductive health.
Understanding the normal fluctuations of LH throughout the menstrual cycle can help provide insight into ovulation patterns. In a typical cycle, LH levels start to surge around day 14 and trigger ovulation within 24-48 hours. After ovulation, LH levels drop during the luteal phase. However, in irregular cycles, the LH peak may be less predictable.
Can LH testing help track ovulation?
Ovulation tracking can be useful when trying to conceive or gain insight into menstrual cycle irregularities.
When performed regularly over multiple cycles, LH testing may help identify ovulation patterns. In most cycles, ovulation occurs 24-48 hours after the LH surge. However, LH testing results can vary for multiple reasons:
- In irregular cycles, the LH peak may be hard to detect due to unpredictability
- The LH surge may precede ovulation at different times in different cycles
- The LH surge may even occur without triggering ovulation
For these reasons, LH testing alone may not precisely pinpoint the timing of ovulation. Working with your healthcare provider for proper interpretation within the context of your health can provide the most meaningful information.
Both urine and blood tests can measure LH levels. Home urine LH test kits are commonly used to detect the pre-ovulation LH surge. A positive result indicates ovulation will likely occur within 24-48 hours, but does not provide the LH level.
In contrast, a luteinizing hormone blood test provides a one-time snapshot of the LH level. If tested regularly and monitored over time, an LH blood test may help with identifying ovulation patterns.
When is LH testing helpful?
In women, LH testing is often conducted along with other hormone tests, such as FSH testing. FSH stimulates the growth of eggs in the ovaries to support ovulation and regulate the menstrual cycle. An LH test, in conjunction with other hormone tests, may help evaluate:
- Ovulation and fertility
- Menstrual cycle or ovulation irregularities
- Perimenopause and menopause transition
- Polycystic ovary syndrome (PCOS)
- Pituitary gland disorders
In men, LH testing may be tested with other hormones to assess:
- Infertility or low sperm count
- Low sex drive
- Low testosterone levels
- Pituitary gland disorders
Note: This test does not diagnose or determine the cause of infertility, menstrual irregularities or any health condition. LH is often evaluated in the context of other hormones such as FSH. This test provides a snapshot of your hormone level at the time of testing; you will receive test results a few days after the sample is collected. It is recommended to consult with a healthcare provider if you have any questions about your results.
Whether you want to learn more about your ovulation patterns, hormone fluctuations or overall reproductive health, monitoring your LH levels over time can provide key insights to discuss with your provider. Labcorp OnDemand’s Luteinizing Hormone (LH) Test offers convenient access to this important fertility hormone test.
