The medical definition of infertility is that no contraceptive measures have been taken for more than one year, normal sex life and unsuccessful pregnancy. Mainly divided into primary infertility and secondary infertility. Primary infertility means never conceived; secondary infertility means infertility after being pregnant. According to this strict definition, infertility is a common problem that affects at least 10% to 15% of couples of childbearing age. The causes of infertility are divided into male infertility and female infertility.
The causes of infertility are divided into male infertility and female infertility. In 1992, the World Health Organization used this classification most widely in the diagnosis and treatment of infertility. The primary cause of diagnosis is in order: ovulation disorders, semen abnormalities, fallopian tube abnormalities, unexplained infertility, endometriosis and others such as immunological infertility. Another factor is cervical factors, including cervical stenosis, which accounts for more than 5% of all cervical factors. Female infertility is mainly caused by ovulation disorders, fallopian tube factors, and abnormal endometrial receptivity. Male infertility is mainly caused by abnormal spermatogenesis and dysregulation.
1. Female infertility
(1) Fallopian tube infertility The fallopian tube plays an important role in picking up eggs and transporting eggs, sperm and embryos; a fallopian tube is also a place where sperm is capacitated, sperm and eggs meet and fertilize. Infections and surgical operations can easily damage the fallopian tube mucosa, and then the loss of cilia, peristalsis, and blockage or adhesion with surrounding tissues, which affect the patency of the fallopian tube. Therefore, blocked or unobstructed fallopian tubes are important reasons for female infertility. ① Infection. Pelvic infection is the main factor leading to tubal infertility. Infection not only causes obstruction of the fallopian tubes but also scarring, which makes the wall of the fallopian tube stiff and adhesion around the fallopian tube, changes its relationship with the ovary and affects the oviduct's function of picking up and transporting eggs. Infected pathogens can be caused by aerobic and anaerobic bacteria, and can also be caused by chlamydia, tuberculosis, diplococcus gonorrhoeae, and mycoplasma. ②Endometriosis Pelvic endometriosis and ovarian endometriosis can form peritoneal adhesions, which can cause adhesion outside the fimbriae of the fallopian tube or adhesion around the ovary, so that mature eggs cannot be taken into the fallopian tube; Extensive adhesions can also affect the operation of the fertilized egg. ③Tubal tuberculosis Tubal tuberculosis is the most common in genital tuberculosis, which manifests as thickening and hypertrophy of the fallopian tube, eversion of the umbrella end like a pipe, or even closed umbrella end; the fallopian tube is stiff, nodular, and part of the tuberculosis can be seen with cheese-like masses or miliary peritoneum. Nodules. About half of tubal tuberculosis patients also have endometrial tuberculosis. ④Hydrosalpinx caused by tubal sterilization is more common, which has become an important factor affecting function after tubal recanalization. The pathological changes of the tissues and cells of the proximal fallopian tube after sterilization are related to the length of sterilization time. Therefore, the longer the sterilization time, the lower the success rate of recanalization.
(2) Infertility caused by ovulation disorders Chronic ovulation disorders are a common manifestation of many endocrine diseases, accounting for 20% to 25% of women. The clinical manifestations are mainly irregular menstruation or even amenorrhea, and the cycle is shorter than 26 days or longer than 32 days, suggesting abnormal ovulation. The medical history can also reflect the signs of endocrine disorders such as hirsutism, virilization, galactorrhea, and hypoestrogen. In 1993, the World Health Organization (WHO) formulated the classification standard for anovulation, which is divided into three categories. WHO type I (low gonadotropin-induced anovulation), WHO type II (normal gonadotropin-induced anovulation), WHO III type (high gonadotropin-induced anovulation). WHO type I: including hypothalamic amenorrhea (stress, weight loss, exercise, anorexia nervosa and others), Kallmann syndrome (abnormal migration of gonadotropin-releasing hormone precursor cells) and gonadotropin deficiency. The typical manifestation is hypogonadotropic hypogonadism: low FSH, low E2 and normal prolactin and thyroxine. WHO type Ⅱ: most of the patients encountered clinically. That is, ovarian dysfunction with normal gonadotropins, accompanied by varying degrees of anovulation or oligomenorrhea. Including PCOS, follicular cell hyperplasia and HAIRAN syndrome (hirsutism, anovulation, insulin resistance and acanthosis nigricans). Typical manifestations are: FSH, E2 and prolactin are normal, but LH/FSH is often abnormally elevated. WHO type III: Patients are mainly terminal organ defects or resistance, manifested as hypergonadotropic hypogonadism, including premature ovarian failure and hypogonadism (ovarian resistance). Typical manifestations are elevated FSH and LH, and low E2. Such patients are characterized by a poor response to ovulation induction, and ovarian function has decreased.
(3) Autoantibodies related to infertility are currently divided into two categories: non-organ-specific autoantibodies and organ-specific autoantibodies. The former refers to antibodies against common antigens existing in different tissues, such as antiphospholipid antibodies (APA), antinuclear antibodies (ANA), anti-DNA antibodies, etc.; the latter refers to antibodies that only target a specific organ tissue self-antigen, such as antisperm Antibody (ASAb), anti-ovarian antibody (AOVAb), anti-endometrial antibody (AEMAb) and anti-chorionic gonadotropin antibody (AhCGAb), etc. At present, the nature of the antigens targeted by non-organ-specific autoantibodies is relatively understood, and the technologies for detecting APA and ANA are relatively mature and standard, and clinical data are abundant; while the antigen components targeted by organ-specific autoantibodies are complex, and the degree of standardization of detection is low, they The relationship with infertility is also difficult to clarify due to the difficulty of testing data analysis and statistics, which affects the treatment of infertile patients with positive autoantibodies.
(4) Unexplained infertility When all the indicators checked by an infertile couple are normal, and the cause of infertility cannot be explained, it is diagnosed as unexplained infertility. It is speculated that the causes of unexplained infertility may include the following aspects: ①Poor cervical secretions; ②Poor endometrial receptivity to early embryos; ③Poor peristalsis of the fallopian tube; ④Defective function of collecting eggs at the fimbriae of the fallopian tube ⑤Luteinized non-rupture syndrome; ⑥Slight hormone secretion, such as insufficient corpus luteum function; ⑦Sperm and egg fertilization impaired; ⑧Mild endometriosis; ⑨Immune factors, such as anti-sperm antibodies, anti-sperm antibodies Zona pellucida antibody or anti-ovarian antibody; ⑩ peritoneal macrophage function is abnormal; the antioxidant function in the peritoneal fluid is impaired.
2. Male infertility
(1) Reproductive organs and other abnormalities ①Congenital abnormalities: Congenital developmental abnormalities of the testis include anorchidism, Klinefelter, XYY syndrome, and male pseudohermaphroditism. The karyotype of Klinefelter syndrome is mostly 47,XXY; the breasts of patients are feminized; the testis is small and hard, the seminiferous tubules are hyaline and fibrosis, spermatogenesis stops completely or is severely reduced. Abnormal testicular descent is also an important cause of male infertility. When the testis descends abnormally, the number of germ cells in the seminiferous tubules decreases, the volume of the testis decreases, and the weight also decrease. The higher the position of the testis in the abdominal wall or in the abdominal cavity, the greater the damage to the seminiferous tubules. Patients with abnormal bilateral testicular descent are unlikely to have children without treatment. ② Vas deferens obstruction: congenital absence of the vas deferens and seminal vesicles, characterized by low semen volume, often less than 1ml, and no fructose in seminal plasma; inflammatory obstruction, such as bilateral epididymal tuberculosis; ejaculatory duct obstruction is rare. Surgical injury or vasectomy, etc.; as well as prostatitis and seminal vesiculitis, can cause a significant decrease in semen quality. ③ Varicocele: It can lead to blood stasis in the testis, reduce effective blood flow, destroy the normal microenvironment of spermatogenesis, and eventually degenerate and shrink spermatogonia, reduce sperm production, weaken vitality, and increase abnormal sperm. In severe cases, it can No sperm. ④Androgen target organ disease, divided into two types: complete such as testicular feminization; incomplete such as Reifenstein syndrome.
(2) Abnormal endocrine ①The main reason is gonadotropin synthesis or secretion dysfunction. Kallmann syndrome, also known as selective hypogonadotrophic hypogonadism, is hypothalamic GnRH pulse release dysfunction and is an autosomal recessive genetic disease. The clinical features are sexual maturity disorder, accompanied by loss of sense of smell, small testicles, abnormal testicles, small penis, and hypospadias. Serum testosterone levels are low, and LH and FSH levels are at the lower limit of normal values for the same age group. ②Selective LH deficiency: The patient's serum FSH level is normal, LH and testosterone levels are low, virilization is insufficient, breast development, but the size of the testis is normal, and there are a few sperm in the semen, so it is also called "fertility" anorchid syndrome. ③Pituitary tumors have the most obvious impact on the secretion of LH. Pituitary tumors are the most common cause of hyperprolactinemia. Excessive PRL can lead to loss of libido, erectile dysfunction, breast development, galactorrhea and spermatogenic dysfunction. ④In adrenal hyperplasia, 21-hydroxylase deficiency is often associated with infertility. The reduction of corticosteroid synthesis causes an increase in ACTH. The adrenal cortex is over-stimulated by ACTH to synthesize a large amount of testosterone, which inhibits the secretion of pituitary gonadotropin. This leads to infertility.
(3) Sexual dysfunction includes loss of libido, erectile dysfunction, premature ejaculation, non-ejaculation and retrograde ejaculation, etc. Semen cannot be injected into the vagina normally.
(4) Immune factors are divided into two categories, anti-sperm autoimmunity produced by men and anti-sperm alloimmunity produced by women. Sperm and the immune system are isolated due to the blood-testis barrier. Therefore, whether for men or women, sperm antigens are foreign antigens and have strong antigenicity. The blood testis barrier and the immunosuppressive factors in the seminal plasma have jointly established a complete immune tolerance mechanism. When orchitis, epididymitis, prostatitis, seminal vesiculitis occurs, or after vasectomy, the above immune tolerance The mechanism is destroyed, that is, an anti-sperm immune response may occur.
(5) Infectious factors Mumps virus can cause orchitis. In severe cases, it can cause permanent damage and atrophy of the seminiferous tubules, resulting in testicular failure; Treponema pallidum can also cause orchitis and epididymitis; gonorrhea, tuberculosis, filariasis Can cause vas deferens obstruction; semen chronic bacterial infection, or mycoplasma, chlamydia infection can increase the white blood cell count in the semen, reduce semen quality, and increase immature sperm.
(6) Physical and chemical factors and environmental pollution The seminiferous epithelium is a rapidly dividing cell, so it is easy to accept damage from chemical factors. ① Heat, radiation and toxic substances can cause the seminiferous epithelium to fall off, or affect the function of mesenchymal cells and supporting cells, and hinder the spermatogenesis process. The seminiferous epithelium is sensitive to radiation. Cyclophosphamide, nitrogen mustard and other chemotherapeutic drugs directly damage the function of the seminiferous epithelium and mesenchymal cells. ② Certain environmental toxins have similar functions or structures to natural hormones, such as polychlorinated biphenyls (PCB), tetrachlorobiphenyl (TCDD), dichlorodiphenyl dichloroethane (DDT), diethylstilbestrol (DES), etc. These toxins affect human health by polluting the air, water and food chain, including the continuous decline in the quantity and quality of male sperm.
(7) Medical surgery history Opioids, anticancer drugs, chemotherapy and antihypertensive drugs can directly or indirectly affect sperm production. Past pelvic surgery history, bladder, prostate surgery history may cause decreased ejaculation function; hernia repair or testicular fixation may affect the spermatic cord or testicular blood supply.
(8) Unexplained infertility. About 31.6% of male infertility patients still cannot find the exact cause after the current commonly used examination methods.
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