Why do some women not grow pubic hair?

　　Pubic hair is one of the signs of sexual development. It generally coincides with the beginning of breast development. Its growth can be divided into 5 stages:

　　The first stage: before the age of 11, there is no pubic hair growth, only fine hairs are seen on the mons pubis, and the color is light, which is called childish type.

　　The second stage: 11-12 years old. Under the stimulation of sex hormones, pubic hair begins to sprout. First, light-colored, sparse, soft, and straight pubic hair appears in the labia majora, and then in the mons pubis.

　　The third stage: 12-13 years old, the color of the pubic hair deepens, begins to become dense, hard, thick, lengthened, and curled, covering the mons pubis triangle;

　　The fourth stage: 13-14 years old, continues to become thicker, similar to the appearance of an adult woman, its upper limit is mostly limited to the mons pubis, has not yet expanded to the inner thigh, and no longer expands upward.

　　The fifth stage: 14-15 years old, the pubic hair is thick and spreads widely, rolling up the entire vulva, covering the labia majora along the pubic bone, converging with the anus, and reaching the inner thigh, showing a typical adult appearance female pubic hair.

　　Armpit hair appears late and is usually the last to appear in the development of secondary sexual characteristics in women. Most of them don't grow until after the age of 17.

　　The growth of human hair is mainly controlled and restricted by androgens and estrogens. They have specific stimulating or inhibiting effects on the growth of hair in different parts of the body. Therefore, the distribution of hair in men and women is different. However, other primates rarely have this gender difference. The secret is still difficult to explain. For example, estrogen promotes hair growth, while androgens inhibit the growth of hair on both sides of the forehead, so male Men's hair is not as thick as women's, and has a specific concave hairline. Another example is that androgens stimulate the growth of beards and chest hair, while estrogen inhibits their growth, so men have beards and chest hair (yellow men are rare), but women have neither. Estrogen and androgen both stimulate armpit and pubic hair, so both men and women grow armpit and pubic hair (although the distribution characteristics of pubic hair are different between men and women). The growth of body hair in men and women is mainly controlled by the androgen (dehydroepiandrosterone) secreted by the adrenal cortex. When women suffer from adrenal insufficiency, hair loss occurs. Hair can grow back after androgen injection. When men remove their testicles, their beards stop growing, but their armpit and pubic hair remain unchanged.

　　So why do some women have no pubic or armpit hair? One reason is that the level of androgens in women is low; the other reason is that the androgen receptors in the hair follicles of the pubic area and axilla are insensitive to androgens or have other defects, and some have no such receptors at all. When pubic and armpit hair is highly scarce or absent, it is called hypotrichosis, which accounts for about 2% of the population. 5%. The endocrine, menstrual cycle, sexual characteristics development, sexual function and fertility of most women with hypotrichosis are normal. Therefore, hypotrichosis is physiological and will not affect their health. healthy There is no need to worry about having a happy married life, let alone believe the lies spread and be swayed by feudal superstition. I hope that tragedies such as family disintegration or even suicide will not occur in the future.

　　It is worth mentioning that there are also a few cases of hypotrichosis that are pathological, such as a sex chromosome abnormality genetic disease called Turner syndrome. The patient's chromosomes are mostly 45, This kind of woman sexually transmitted diseases Human gonadal insufficiency is characterized by low stature, webbed neck, underdeveloped breasts, immature external genitalia, hairless or oligotric mons pubis, and the absence of follicles in the ovaries. amenorrhea , although they can have sex but have no fertility. Women with hypothyroidism have no armpit hair and sparse pubic hair. They can have sex but have significantly reduced sexual desire.

　　Simple gonadal dysplasia is also accompanied by oligotrichosis, and fertility can be restored after mild treatment. women Postpartum Massive bleeding can cause hypopituitarism, Sheehan's syndrome, in which the patient is extremely emaciated, amenorrhea, infertile, has gradual loss of hair and pubic hair, is weak, and has extremely low sexual desire. However, these lesions are often accompanied by obvious other symptoms, and they often seek treatment for other problems. If you find that hypotrichosis is accompanied by many changes in other body functions, do not take it lightly. It is best to seek medical treatment as soon as possible. Hospital Examination, symptomatic treatment or treatment.