Exploring The Normal FSH and LH Levels In Females
It is needless to mention that both FSH and LH aid in regulating reproductive functions in our bodies. In other words, both these hormones go hand-in-hand to facilitate the follicles’ growth stimulation and subsequent ovulation in a normal way. The synergy between these hormones is that which keeps the reproduction organs intact and functioning. Having acknowledged this fact, the current article, therefore, serves to provide a normal reference range of both these hormones in females in the first place, going further to provide a list of tests utilized to measure their levels. Additionally, through the symptoms associated with both high and low-level FSH and LH levels in females, this article serves to first and foremost identify the factors bringing about such variations, moving on to suggest methods to optimize the same.
Normal FSH and LH Reference Range Chart for Females
It is needless to state here that the function of LH is complementary to that of the FSH in stimulating follicles growth and ovulation. In this regard, it’s also important to note the normal reference range levels for females, though we previously acknowledged the FSH levels that should be for each age group in the concerned population.
Figure 1: Normal FSH and LH Reference Range for Adult Females
Figure 1 above represents normal reference ranges for both FSH and LH in adult females. As could be interpreted from here, the early follicular release is the first to demonstrate a 3-10 IU/L of FSH and 2-8 IU/L of LH. Similarly, the mid-cycle peak FSH ranges between 4 and 25 IU/L, with the normal reference range of LH being 10 to 75 IU/L. In the post-menopausal state, a marked increase in FSH is seen, which is greater than 25 IU/L and LH greater than 15 IU/L. Lastly, during pregnancy, FSH significantly goes down to less than 1 IU/L with a proportionate decrease in LH to 2-9 IU/L
Since it is the anterior pituitary gland that releases the follicles-stimulating and luteinizing hormones, these are in fact, stimulated by the pulsatile release of the gonadotropin-releasing hormone (GnRH) in its hypothalamic region (BPACnz, 2023).
While high pulsations result in the secretion of the LH, low pulsating activity causes the release of the FSH. However, the negative feedback of estrogen highly affects these processes, resulting in low FSH and LH levels in the process. At the same time, a surge in the mid-cycle phase of LH results in ovulation, in turn, reinforcing that both FSH and LH complement each other in their functions.
Symptoms related to variations in FSH and LH Levels
High and Low FSH Levels
Notably speaking, high FSH levels in females are not associated with any specific symptoms, other than signifying the onset of menopause. The above symptoms are accompanied by vaginal dryness, irregularity in menstrual cycles, disturbed sleep patterns, emotional changes (mood swings), and bone loss.
Symptoms associated with low FSH levels, on the other hand, have included delayed puberty, infertility, and delays in sexual development (Nall, 2023).
High and Low LH Levels
As could be logically inferred, changes in FSH levels affect those of LH as well. Adhering to this fact is that while high LH levels result in problems with fertility, and irregular or ceasing menstrual cycles, low LH is characteristic of symptoms, including, but not limited to delayed puberty, decreased sexual drive, and decrease in ovulation (MedlinePlus, 2020).
Factors Causing Variations in FSH and LH Levels
Potential factors causing FSH and LH-levels variations have included pituitary gland disorders, hormonal disruption, and certain hereditary issues affecting the hypothalamus.
Pituitary Gland Disorders: A condition called hypopituitarism has the potential to affect the production of one, multiple, or all the hormones released by the pituitary gland.
Hormonal Disruption: The way estrogen is produced impacts the release of both FSH and LH hormones in different ways. While chronic estrogen exposure slows down the production of FSH, the rising levels of estrogen before ovulation give rise to the increased production of FSH and LH (gonadotropins).
Inherited Conditions: Specific inherited conditions such as long-term estrogen exposure in women can produce negative feedback to the brain to inhibit the secretion of FSH (Orlowski and Sarao, 2023). Since estrogen is released by the female reproductive organ, this condition is likely to result in hypogonadotropic hypogonadism.
Tests to Measure FSH and LH Levels
People always take tests for both FSH and LH levels together because the pituitary gland produces both of these hormones. Doctors do this to improve sexual functions by regulating them. Depending on the gender, whether it’s male, female, or child, doctors conduct the tests in different ways (MedlinePlus, 2023). Researchers have understood that LH in women assists in ovulation by triggering the release of eggs. Therefore, achieving an accurate measurement of the hormones released by the pituitary gland is possible only when combining LH with FSH… In women, doctors perform both FSH and LH tests for the following reasons
- To detect infertility
- Find out the exact time of ovulation
- Rationalizing the cause for irregular or stopped menstruation
- Confirming the start of menopause and perimenopause.
Detecting Infertility: For women who have been unsuccessfully trying to conceive for 12 months.
Ovulation time/date: Both FSH and LH, especially the latter, are useful in predicting the exact time or date of ovulation.
Cause for irregular or stopped menstruation: LH tests can effectively reveal the cause of irregular/stopped menstrual periods by measuring the levels before and after ovulation, which will further help in confirming perimenopause or menopause.
Methods to Optimize FSH and LH Levels
Both high and low FSH and LH levels require optimization by applying specific methods. Note here that while we can easily normalize high FSH-cum-TSH levels, we cannot say the same for the opposite case, i.e., transitioning from lower to normal levels is not as easy. The need to prescribe appropriate dietary or medication regimens relies on factors that cause them. As discussed earlier, hormonal disruptions, certain inherited conditions, and pituitary gland disorders significantly affect the production of both FSH and LH, in turn, causing delayed puberty, reproductive abnormalities, and hypogonadotropic hypogonadism. Working on these factors will hopefully help address the low levels of FSH and LH, also with the introduction of appropriate dietary changes, and medications, as stated above. Additionally, researchers have identified LH beta-subunit mutations, Idiopathic hypogonadotropic hypogonadism, and stress-related hypogonadotropic hypogonadism as hypothalamic causes. On the other hand, pituitary causes encompass hyperprolactinemia and Sheehan syndrome.
Kallmann Syndrome:
A congenital form of LH deficiency, and presents as hypo or anosmia. Genetic mutations are highly attributable to this condition, resulting in differentiation or migration failure of the neurons related to the gonadotropin-releasing hormone
LH beta-subunit mutations:
These tend to inactivate the mutations in the FSH and LH receptor beta subunits to result in infertility and amenorrhea.
Idiopathic Hypogonadotropic Hypogonadism:
There can be seen the absence of GnRH-induced FSH and LH release either completely or partially.
Stress-related hypogonadotropic hypogonadism:
Excessive amounts of strenuous physical activities (exercise) and a strict weight loss regime can result in this condition.
Hyperprolactinemia:
As the name suggests, hyperprolactinemia results from the pituitary tumor that secretes prolactin, inhibiting the release of the FSH and LH in the process to further cause hypogonadism, galactorrhea, and infertility.
Sheehan Syndrome:
The Massive hemorrhage during childbirth is the main culprit behind the Sheehan Syndrome occurrence. The long-term effect is the ischemic infarction of the ischemic gland.
Also Read: Low FSH Level Symptoms
Conclusion
The FSH and LH hold interconnected functions and assist in stimulating follicle growth and ovulation. Otherwise known as the gonadotropin-releasing hormones, these pituitary gland-generated hormones pave the way for controlling a woman’s reproductive function. The varied FSH and LH levels, both high and low, for various reasons, have additionally called for the need to understand their etiology and idiopathic nature, addressing which will hopefully result in optimizing the same.
