Prepubertal LH concentrations are less than 0.1 IU/L, so LH assays should have a detection limit close to 0.1 IU/L. In cases of central precocious puberty, basal LH concentration usually is ≥0.3 IU/L.
§ In most laboratories, the upper limit of normal for LH after GnRH stimulation is 3.3 to 5.0 mIU/mL. Stimulated LH concentrations above this normal range suggests CPP. ¥ A peak stimulated LH:FSH ratio <0.66 usually suggests nonprogressive precocious puberty, whereas a ratio >0.66 is typically seen with CPP.
It has been well documented that both LH and inhibin B levels increase during puberty, particularly early puberty. Mean circulating levels of LH, together with the other gonadotropin, follicle-stimulating hormone (FSH), increase beginning before physical changes of puberty begin (11).
Low levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (in girls) and testosterone (in boys) may indicate that a hormonal deficiency is causing delayed puberty. High levels of LH and FSH indicate that primary ovarian or testicular insufficiency is causing delayed puberty.
Luteinizing hormone in infants and children
During puberty, LH stimulates both ovaries and testes to make more testosterone. In the ovary, testosterone is then converted into estrogen. These hormones cause changes related to sexual development.
For girls who are yet to go through puberty (aged around 1–10 years), the normal range is 0.03–3.9 IU/L.
During puberty - 0.3 to 10.0 mIU/mL (0.3 to 10.0 IU/L) Adult - 1.5 to 12.4 mIU/mL (1.5 to 12.4 IU/L)
Abstract. Serum testosterone (T) levels in men decline with age while serum LH levels, as measured by RIA, increase.
Here are normal ranges: Men: 1.24 to 7.8 IU/mL. Women, follicular phase of menstrual cycle: 1.68 to 15 IU/mL. Women, midcycle peak: 21.9 to 56.6 IU/mL.
However, studies show that an LH to FSH ratio of 2 or 3 — meaning LH levels are higher than FSH levels when measured on the same day — may be indicative of polycystic ovarian syndrome (PCOS). This is because many women with PCOS experience elevated LH levels throughout their cycle, even when LH should be low.
The cause of LH hypersecretion in PCOS is probably due to enhanced pituitary sensitivity to gonadotropin releasing hormone (GnRH) or to changes in GnRH secretion patterns rather than increased GnRH secretion [35, 39, 40].
Normal results for adult women are: Before menopause: 5 to 25 IU/L. Level peaks even higher around the middle of the menstrual cycle. Level then becomes higher after menopause: 14.2 to 52.3 IU/L.
The rise in FSH and LH with increasing age is consistent with the decline in testosterone, assuming normal operation of the feedback pathway by which low testosterone level signals the hypothalamic-pituitary axis to release FSH and LH.
As the table demonstrates, normal levels of FSH go from below 7.0 mIU/mL for someone younger than 33 to over 8.5 mIU/mL for a woman over 41.
§ In most laboratories, the upper limit of normal for LH after GnRH stimulation is 3.3 to 5.0 mIU/mL. Stimulated LH concentrations above this normal range suggests CPP. ¥ A peak stimulated LH:FSH ratio <0.66 usually suggests nonprogressive precocious puberty, whereas a ratio >0.66 is typically seen with CPP.
In children, FSH levels are usually low until puberty, when levels begin to rise. In girls, it helps signal the ovaries to make estrogen. In boys, it helps signal the testes to make testosterone.
One large study showed that the median LH on the day before ovulation was about 44.6 mIU/mL, but that LH could be as high as 101, or as low as 6.5. Yep — some women had an LH of 6.5 the day before ovulation!
LH levels are normally low during childhood. Normal result for men over 18 years of age is around 1.8 to 8.6 IU/L. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples.
Usually, in healthy women, the ratio between LH and FSH usually lies between 1 and 2. In polycystic ovary disease women, this ratio becomes reversed, and it might reach as high as 2 or 3 (8).
Diagnosing PCOS with FSH and LH Hormone Levels
FSH and LH are often both in the range of about 4-8 in young fertile women. In women with polycystic ovaries the LH to FSH ratio is often higher – for example 2:1, or even 3:1.
For example, it is typical for women with PCOS to have an LH level of about 18 mlU/ml and a FSH level of about 6 mlU/ml (notice that both levels fall within the normal range of 5-20 mlU/ml).
Levels of LH are low for most of the monthly menstrual cycle. However, around the middle of the cycle, when the developing egg reaches a certain size, LH levels surge to become very high. A woman is most fertile around this time. People refer to this interval as the fertile window or fertile period.