Fsh and lh

Human reproductive function is controlled by the hypothalamic-pituitary complex of the sex glands. Hormonal regulation allows to form the phenotype and sex of a person and provides women with the opportunity for fertilization every month. The body seeks to maintain a stable level of sex hormones in the blood plasma. Consider the ratio of FSH and LH.

Physiological hormonal regulation

The ratio of FSH and LH: what should be

The hypothalamic-pituitary complex, located in the brain, consists of neurons. They are located in the hypothalamus and endocrine system, as well as in the anterior lobe of the pituitary.

The hypothalamus regularly releases neurohormones into the bloodstream - the so-called gonadotropin-releasing hormones, which, reaching the pituitary gland, stimulate its secreting function. In the anterior lobe of the pituitary gland, two types of hormones are synthesized under the action of GnRH: follicle-stimulating (FSH) and luteinizing (LH). These hormones, getting into the general blood circulation, will act on cellular targets in the sex glands.

These glands (testicles in men and ovaries in women) ensure the production of germ cells:

  • gametes that are responsible for the exocrine function of the body;
  • sex hormones that provide endocrine function.

These two important functions are activated during puberty and are regulated by hormonal secretions of the hypothalamic-pituitary complex.

What happens in the body of men?

The hypothalamic-pituitary complex in the body of men controls the activity of the testes from puberty to the end of life. Under the action of FSH, somatic cells, known as Sertoli, stimulate the daily production of millions of sperm cells in the seminiferous tubules.

Under the action of LH, the interstitial tissue located around the seminiferous tubules is secreted by hormone-producing Leydig cells, the male sex hormone, testosterone, is continuously secreted. Subsequently, it modulates its own secretion, affecting the hypothalamic-pituitary complex, which brings the concentration of testosterone to its nominal value.

Hormonal balance in the female body

Hormonal balance in the female body

The hypothalamic-pituitary complex in a woman’s body controls the cyclic activity of the ovaries from the onset of puberty to menopause. In each cycle, under the action of FSH and LH, one of the ovarian follicles contained in the ovary develops, produces oocytes, immature eggs and secretes female sex hormones - estrogen and progesterone. The concentration of these hormones varies depending on the stage of development of the follicle.

Ovarian cycle is divided into three phases and lasts 28 days:

  • Follicular phase. During the first half of the cycle, FSH stimulates the maturation of follicles in the ovaries and the secretion of estrogen.
  • Ovulation. The middle of the cycle, when high levels of LH stimulates the mature follicle and causes the release of the egg, ready for fertilization.
  • Luteal phase. For the next 14 days, LH induces transformation of the corpus luteum after ovulation of the follicle and stimulates the secretion of progesterone and estrogen in it.

During the follicular and luteal phases, estrogen and progesterone are secreted in low concentrations and have a negative effect on the hypothalamic-pituitary complex. The middle of the cycle with a high concentration of female sex hormones, on the contrary, has a positive effect and stimulates LH increase, which causes ovulation of the mature follicle.

Under the influence of cyclic variations in the concentration of estrogen and progesterone, endometrial development occurs. Physiological changes in the endometrium are coordinated with the activity of the ovaries to ensure the possibility of implantation of the embryo into the uterus during fertilization.

The ratio of LH and FSH: the rate and causes of possible deviations

The ratio of LH and FSH: the rate and causes of possible deviations

A blood test for FSH is prescribed to a woman or a man in order to identify potential problems associated with sexual functions:

  • in men, testicular failure;
  • in women, a blood test can diagnose amenorrhea, a predisposition to infertility, or polycystic ovary.

In addition, FSH is often used as a measure of the potential of the ovary - the stock of follicles for maturation.

A blood test for LH is prescribed in such cases:

  • in violation of the menstrual cycles in women to determine the cause of this phenomenon and the possible occurrence of menopause;
  • if necessary, determine the performance of the ovaries;
  • for determining early pregnancy.

Normal values ​​of FSH and LH in women depend on the reproductive phase and look like this.

Reproductive phase

FSH level, honey / ml

LH level, honey / ml

Before puberty



Follicular phase






Luteal phase



During pregnancy






In men, these figures depend on age.

Age of man

FSH level, honey / ml

LH level, honey / ml

Before puberty



from 18 to 70 years






In addition, to assess fertility, you need to figure out what should be the ratio of LH and FSH and an indicator of its norms. How to calculate the ratio of LH and FSH?

For the correct calculation, it is necessary to divide the quantitative content in the blood of LH by the concentration of FSH. The resulting coefficient reflects the state of reproduction and changes with age.

Normal values ​​of the ratio of LH to FSH in women are shown in the table.

Age category

The value of the coefficient of LH / FSH

Before puberty


One year after the first menstruation


2 years after the first menstruation and before menopause


Thus, for women of reproductive age, the ratio of LH to FSH should normally be no more than 2. The increased value of this coefficient may indicate one of these pathologies:

  • Stein-Leventhal syndrome or the so-called polycystic ovary;
  • hormonal imbalance;
  • ovarian failure;
  • pituitary adenoma;
  • early menopause.

Elevated hormonal levels require appropriate treatment with the participation of a qualified specialist. Be healthy!

Add a comment