Luteinizing hormone (LH) plays a key role in gonadal function. LH in synergy with follicle stimulating hormone (FSH) stimulates follicular growth and ovulation. Thus, normal follicular growth is the result of complementary action of FSH and LH.
In both males and females, FSH and LH are rhythmically secreted to control reproductive physiology. In males, these hormones drive the synthesis of testosterone and the production and development of sperm. In females, FSH triggers follicle maturation, and a sudden surge in LH drives ovulation.
FSH and LH levels can help differentiate between a condition affecting the ovaries themselves (primary) and dysfunction of the ovaries due to disorders of either the pituitary or the hypothalamus (secondary). High levels of FSH and LH are consistent with conditions affecting the ovaries themselves.
Key Difference – FSH vs LH
Both hormones are essential during reproductive processes carried out by the body. They are synthesized and secreted by the gonadotropic cells of the anterior pituitary. FSH stimulates the formation of gametes that takes place in the primary sex organs while LH doesn't involve.
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.
Several hormones are involved in the menstrual cycle of a woman: follicle stimulating hormone (FSH ) causes the maturation of an egg in the ovary. luteinising hormone (LH ) stimulates the release of the egg. oestrogen is involved in repairing and thickening the uterus lining, progesterone maintains the uterine lining.
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). As a result of raised LH/FSH ratio, ovulation does not occur in polycystic ovary disease patients (9).
FSH causes ovarian follicles to enlarge and produce estrogen. Over time, fewer and fewer follicles remain to be stimulated and thus estrogen levels decline as a woman ages. This decline in estrogen leads to an increase in FSH as there is not enough estrogen being produced to "turn off" the brain's production of FSH.
Why the Test is Performed. In women, an increase in LH level at mid-cycle causes release of eggs (ovulation). Your doctor will order this test to see if: You are ovulating, when you are having trouble getting pregnant or have periods that are not regular.
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.
Menopause markers
FSH levels are higher than luteinizing hormone (LH) levels, and both rise to even higher values than those seen in the surge during the menstrual cycle. The FSH rise precedes the LH rise; FSH is the diagnostic marker for ovarian failure, while LH is not necessary to make the diagnosis.
Sometimes, elevated follicle-stimulating hormone (FSH) levels are measured to confirm menopause. When a woman's FSH blood level is consistently elevated to 30 mIU/mL or higher, and she has not had a menstrual period for a year, it is generally accepted that she has reached menopause.
Estrogen is at a low point. Therefore, the pituitary secretes FSH and LH, a process which actually begins before the onset of your menses. These hormones in turn stimulate the growth of several ovarian follicles, each containing one egg.
LH and FSH promote ovulation and stimulate secretion of the sex hormones estradiol (an estrogen) and progesterone from the ovaries.
positive feedback triggers the anterior pituitary to release more FSH and LH. more FSH and LH cause the ovary to produce more estrogen.
Women, when they undergo menopause, lose bone and gain body fat. FSH, which rises at menopause, could be responsible for the weight gain and bone loss that many women experience in their middle ages.
High LH levels can signify that your sex organs aren't producing enough steroid hormones needed for a reproductive process to take place. This is typical of when the ovaries and testes have exhausted their ability to produce estrogen and testosterone, from genetic, autoimmune, surgical, or physiologic causes.
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.
Estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) all need to be tested on day 3 of the menstrual cycle to get the most clinically meaningful results.
Now results published in The New England Journal of Medicine and Cell Metabolism have revealed the rise in FSH at the time of the menopause may be responsible for the waist-thickening weight gain.
In females, LH stimulates steroid release from the ovaries, ovulation, and the release of progesterone after ovulation by the corpus luteum [8].
Optimal levels: A typical AMH level for a fertile woman is 1.0–4.0 ng/ml; under 1.0 ng/ml is considered low and indicative of diminished ovarian reserve. Low AMH does not mean that you cannot get pregnant but possibly a long road to motherhood.
When it comes to females low estrogen count can lead to infertility on multiple grounds. Reduced estrogen level may be because of pituitary gland issues, such as in the case of excessive exercise, being underweight or having an eating disorder, leading to not releasing enough eggs during ovulation.