Female hormones

Hormones, as they affect a woman’s reproductive health – from menstruation, pregnancy, menopause and more – also have many important effects on her overall health. The best known female sex hormones are estrogen and progesterone. But women’s bodies also produce and use many other types of hormones that affect other aspects of their lives, from energy levels, weight, mood and more. For example testosterone: although it is considered a male hormone, women also produce and use a small amount.

All stages of female reproductive life (endocrine function) are regulated by sex hormones: estrogen, progesterone and a small amount of androgens. Let’s see them separately.


The main female hormone is estrogen. It is mostly made in the ovaries, but small amounts are made in the adrenal glands and fat cells. The placenta also produces estrogen during pregnancy.

Estrogens play an important role in puberty, menstruation, pregnancy and menopause:
they affect the brain, cardiovascular system, hair, musculoskeletal system, skin and urinary tract.

The main ovarian estrogen is estradiol: the others are estrone and estriol. Its levels vary greatly during the menstrual cycle. Its normal values ​​are:

  • less than 50 pg/ml in the follicular phase;
  • between 250 and 400 pg/ml in the ovulatory phase;
  • between 100 and 200 pg/ml in the luteal phase;
  • less than 20 pg/ml in menopause.


The ovaries secrete the female sex hormone progesterone after ovulation . The placenta also produces them during pregnancy.

The role of progesterone is:

  • prepare the lining of the uterus for the fertilized egg,
  • support pregnancy,
  • suppress estrogen production after ovulation.

Progesterone levels can be measured through a blood test . Normal progesterone levels in women are,

  • in the follicular phase, 0.1-1.5 ng/ml;
  • in the ovulatory phase, 1.5-2.5 ng/ml;
  • in the luteal phase, 1.5-30 ng/ml;
  • in menopause, 0,2-1,0 ng/ml;
  • pregnant:
    • I trim.:9,0-50 ng/ml;
    • II trim.: 20-150 ng/ml;
    • III trim.:60-250 ng/ml


Testosterone is a hormone that falls into the category of androgens. In women, small amounts of testosterone come from the adrenal glands and ovaries. In the woman’s body this hormone plays a role in sexual desire, regulation of the menstrual cycle and strength.

Female hormones in childhood

Although we tend to associate hormones only with our puberty, in reality they influence our body since our childhood.

For example: In newborn babies, boys or girls, hormones may cause enlargement of one or both breasts, sometimes accompanied by the production of a small amount of milk.

For a long time it was thought that this breast development (in children) was due to the mother’s estrogens which passed through the placenta during pregnancy, stimulating this phenomenon in the newborn.

According to another hypothesis, the drop in maternal estrogen levels in the child’s circulation would cause a contrary reaction in the brain of the newborn, which would lead to the production of another typically female hormone called prolactin, which hormone is capable of  causing a certain breast enlargement, enlargement which however disappears after a few weeks.

Slight breast enlargement may reappear in the first two years in young girls, but in this case it is the girl’s hormones that affect her breast tissue. This fact could come and go in the following months (or even years), and then disappear in the course of growth.

Female hormones during puberty

Hormones cause some of the biggest and most lasting changes in a girl’s body during puberty.

  • Her breasts become larger and take on the typical appearance of those of an adult.
  • Hair appears in the armpits and pubic hair.
  • The girl often grows in height suddenly.
  • Finally, her period begins: usually when her growth in height is arrested.

From start to finish, the process of puberty takes at least four years.

As they leave infancy through adolescence, some girls (as might be expected) struggle. to adapt, to all those changes that take place in their bodies, to their emerging sexuality at the beginning of their fertile period, to a certain degree of emotional turbulence.

  • All that ;is needed; for the period of puberty, it exists from birth, but the organism keeps it quiescent.
  • Finally, in puberty the hormones, which were previously ;controlled;, become ;free; to produce their effects on the body.

A part of the brain called the hypothalamus begins to release, by means of increasingly frequent pulsations and in ever greater quantities, a hormone called the gonadotrope: it is the hormone that influences the function of the gonads.

This event stimulates the pituitary gland (which is located in the brain very close to the hypothalamus) to produce luteinizing hormone (LH) and follicle stimulating hormone (FSH) which initiate hormone production in the ovaries.

Female hormones during menstruation

The first menstrual period ( menarche ) occurs about two or three years after the beginning of breast development: for all women it is different, but for most of them it occurs between the ages of 10 and 16.

Follicular phase

Each month, the uterus thickens: in preparation for a fertilized egg. When there are no fertilized eggs, estrogen and progesterone levels remain low. This fact pushes the uterus to shed its lining.
The day the woman starts bleeding. it is day 1 of her cycle, or the follicular phase.

The pituitary gland begins to produce a little more FSH hormones. This stimulates the growth of follicles in the ovaries. Inside each follicle is an egg.
As sex hormone levels decrease, only a single dominant follicle will continue to grow.

As this follicle produces more estrogen, the other follicles break down. Higher estrogen levels stimulate a surge in luteinizing hormone (LH). This stage lasts about two weeks.

ovulatory phase

This is followed by the ovulatory phase. LH causes the follicle to rupture and the egg to be released. This phase lasts from 16 to 32 hours.
Fertilization can only occur for about 12 hours after the egg has left the ovary.

Luteal phase

The luteal phase begins after ovulation. The ruptured follicle closes and progesterone production increases.
This prepares the uterus to receive a fertilized egg.
If this does not happen, estrogen and progesterone decrease again and the cycle begins again.

The entire menstrual cycle lasts approximately 25-36 days. Bleeding lasts 3 to 7 days. But even this period can vary quite a lot. Your cycle may be quite irregular for the first few years. It may also vary at different times in your life or when you use hormonal contraceptives.

Hormones during pregnancy

If the egg released from the ovary is fertilized, thus giving rise to a zygote, the production of female hormones changes dramatically.
The usual downward curve that affects both estrogen and progesterone no longer occurs, and therefore the menstrual cycle no longer appears.

A new hormone produced by the developing placenta called  human chorionic gonadotropin (hCG) stimulates the ovaries to produce higher levels of estrogen and progesterone, so they can support the pregnancy.

Most pregnancy tests  are designed to be able to detect hCG in urine or blood. Usually these are very sensitive analyzes as they are able to recognize them even in minimal quantities.

In the fourth month of pregnancy, the placenta replaces the ovaries as the major producer of estrogen and progesterone. These hormones cause a thickening of the uterine lining, increase the amount of circulating blood (in particular by increasing its supply to the uterus and breasts), relax the abdominal muscles enough to allow the fetus to grow.

Progesterone and a different other hormone,  relaxin promote relaxation of the ligaments and muscles. The increased joint mobility of the pelvis prepares it for the passage of the baby during delivery.

During delivery, other hormones help contract the uterus during and after labor, and stimulate the production and release of mother’s milk.

Hormones after childbirth

After childbirth the levels of estrogen, progesterone and other hormones drop sharply causing a number of physical changes.

The uterus returns to its original size; pelvic floor tone improves, and circulating blood volume returns to normal.

These major changes in hormone levels may play an important role in the onset of  postpartum depression: however since no differences in hormone decline were found between women with and without this condition, it could be that some of they are more easily affected by hormonal fluctuations than others.

Speaking of hormonal fluctuations, it must be said that although these have been extensively studied for many years, we still don’t know if they are to be considered responsible for the high number of physical and psychological symptoms, collectively called premenstrual syndrome or PMS.

In fact, many women, before the period, experience breast swelling, abdominal swelling, irritability, a bad mood and other symptoms, but it is not known whether these effects are due to hormonal fluctuations, changes in the molecules of the brain, social and emotional problems, or a combination of all three.

For most women, a major hormonal change occurs around the time of the last menstrual period.

A woman is said to be in menopause when she hasn’t had a period for a year.

The average age at which women reach menopause is 51/54
years. If it occurs before the age of 40, it is called premature menopause.

The normal functioning of the ovaries begins to fail between five and ten years before the last menstrual period, thus causing changes in menstruation which become shorter or longer and sometimes irregular. The cycle could be stronger or lighter.

The ovaries will eventually produce such a small amount of estrogen that the lining of the uterus will no longer thicken, and menstruation will no longer occur.

Estrogen helps protect the heart and bones, and maintains the breasts, uterus, vagina and bladder for most of a woman’s life.

Thus, that marked loss of estrogen that occurs during menopause can also have harmful effects on a woman’s health. It can also lead to some unwanted symptoms such as depression, irritability and poor concentration: but it’s not necessarily a disastrous moment; in women’s life.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform, Maternicity.com.

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