Infertility is a serious medical problem that affects the physical and especially the mental state of men and women. According to data from the World Health Organization (WHO), worldwide there are between 48 million couples and 186 million people suffering from infertility. Infertility is defined as failure to conceive within 12 months after practicing unprotected sexual intercourse in women under 35 years of age or failure to achieve pregnancy within 6 months after practicing unprotected sexual intercourse in patients over 35 years of age. The probability of pregnancy in a healthy couple is 20-25% per month, i.e. 50% of patients will be pregnant by the third month of trying to conceive, and 75% by the sixth. In Bulgaria, the number of families suffering from infertility is about 200,000. The etiology of infertility in women is quite diverse. There are two main types of sterility: Primary sterility – non-occurrence of pregnancy in the absence of a previous pregnancy; Secondary sterility – non-occurrence of pregnancy in previous births, abortion or ectopic pregnancy. The most common cause of infertility in women is ovarian pathology. It covers about 35-40% of infertility cases, followed by fallopian tube pathology (30%), cervical (5-10%) and vaginal (5-10%), uterine body diseases. In addition to organic causes, the causes of infertility can also be psychological – many couples have neither a female nor a male factor responsible for infertility, and yet they cannot realize their dream of a child. Disorders of ovarian function are the main cause of infertility in women – the so-called. endocrine sterility. The hypothalamus-pituitary-ovary axis plays a major role in ovarian function, which is why a disturbance at any level leads to disturbances in the menstrual cycle. The hypothalamus produces gonadotropin-releasing hormone (GnRH), under the influence of which the pituitary gland secretes follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH are important for the release of a mature egg (ovulation) and disturbances in their synthesis lead to anovulation and lack of possibility of pregnancy. Estrogens are produced in the ovaries under the control of FSH and LH. Of the disorders of ovarian function, polycystic ovary syndrome (PCOS) is common. It causes normgonadotropic amenorrhea and is characterized by anovulatory cycles, clinically or laboratory hyperandrogenism, and/or ultrasound-proven polycystic ovaries. The cause of anovulation can be disturbances in the activity of the hypothalamus, the so-called. hypogonadotropic (hypothalamic) amenorrhea. The cause of these disorders is usually excessive physical exertion, anorexia, severe stress. Premature ovarian failure is a manifestation of another type of ovulation disorder – hypergonadotropic anovulation. It manifests with a lack of ovarian function before the age of 40.The causes can be chromosomal abnormalities (most often Turnot’s syndrome), genetic defects in FSH and LH receptors, infections, autoimmune diseases, etc. Endocrine sterility is also caused by adenomas of the pituitary gland – most often prolactinomas. Excessive prolactin secretion leads to suppression of GnRH production, reduced LH production and anovulation. Disorders in the function of the thyroid gland – hypo- or hyperthyroidism, as well as disorders of the adrenal glands (congenital adrenal hyperplasia) can also be added as a cause of endocrine sterility. In second place in terms of frequency after ovarian pathology is fallopian tube pathology – the so-called. tubal sterility. Pathophysiologically, tubal sterility is due to adhesions in the fallopian tubes and to neighboring organs, which disrupt tubal peristalsis and make it impossible for the egg to move and be fertilized. Past infections (pelvic inflammatory disease, chlamydial infection and other sexually transmitted infections), infections after abortion, ectopic pregnancy, operations in the area of ​​the small pelvis, etc. can lead to tubal sterility. Diseases of the cervix that affect fertility are divided into anatomical and functional. Anatomical problems include conization of the cervix, stenosis of the cervical canal, congenital malformations, etc., and functional problems are related to changes in the cervical mucus. Diseases of the uterus lead to sterility by two mechanisms. The first is associated with space-occupying processes such as uterine fibroids, adhesions, polyps, preventing the implantation of the fertilized ovum, and the second, congenital anomalies of the uterus (hypoplastic uterus, bicornuate, unicornuate, septate uterus), leading to a reduced volume of the uterine cavity and inability to fetal development. Another common cause of infertility in women is endometriosis, which is characterized by the spread of endometrial lining outside the uterine cavity – in fallopian tubes, ovaries, abdominal organs, etc. The etiology of endometriosis is not fully understood, but it is certain that 40 to 50% of women with endometriosis suffer from infertility. The causes of infertility in women are extremely diverse. In the next part of the article, we will consider methods of diagnosis and treatment of the various causes of infertility. Bibliography 1. Gynecology edited by Prof. Dr. Angel Dimitrov, MD, PhD. and Prof. Dr. Viktor Zlatkov, MD. 2. Female Infertility – StatPearls – NCBI Bookshelf (nih.gov) 3. Causes and Prevalence of Factors Causing Infertility in a Public Health Facility (nih.gov) 4. Infertility (who.int)Disorders in the function of the thyroid gland – hypo- or hyperthyroidism, as well as disorders of the adrenal glands (congenital adrenal hyperplasia) can also be added as a cause of endocrine sterility. In second place in terms of frequency after ovarian pathology is fallopian tube pathology – the so-called. tubal sterility. Pathophysiologically, tubal sterility is due to adhesions in the fallopian tubes and to neighboring organs, which disrupt tubal peristalsis and make it impossible for the egg to move and be fertilized. Past infections (pelvic inflammatory disease, chlamydial infection and other sexually transmitted infections), infections after abortion, ectopic pregnancy, operations in the area of ​​the small pelvis, etc. can lead to tubal sterility. Diseases of the cervix that affect fertility are divided into anatomical and functional. Anatomical problems include conization of the cervix, stenosis of the cervical canal, congenital malformations, etc., and functional problems are related to changes in the cervical mucus. Diseases of the uterus lead to sterility by two mechanisms. The first is associated with space-occupying processes such as uterine fibroids, adhesions, polyps, preventing the implantation of the fertilized ovum, and the second, congenital anomalies of the uterus (hypoplastic uterus, bicornuate, unicornuate, septate uterus), leading to a reduced volume of the uterine cavity and inability to fetal development. Another common cause of infertility in women is endometriosis, which is characterized by the spread of endometrial lining outside the uterine cavity – in fallopian tubes, ovaries, abdominal organs, etc. The etiology of endometriosis is not fully understood, but it is certain that 40 to 50% of women with endometriosis suffer from infertility. The causes of infertility in women are extremely diverse. In the next part of the article, we will consider methods of diagnosis and treatment of the various causes of infertility. Bibliography 1. Gynecology edited by Prof. Dr. Angel Dimitrov, MD, PhD. and Prof. Dr. Victor Zlatkov, MD. 2. Female Infertility – StatPearls – NCBI Bookshelf (nih.gov) 3. Causes and Prevalence of Factors Causing Infertility in a Public Health Facility (nih.gov) 4. Infertility (who.int)Disorders in the function of the thyroid gland – hypo- or hyperthyroidism, as well as disorders of the adrenal glands (congenital adrenal hyperplasia) can also be added as a cause of endocrine sterility. In second place in terms of frequency after ovarian pathology is fallopian tube pathology – the so-called. tubal sterility. Pathophysiologically, tubal sterility is due to adhesions in the fallopian tubes and to neighboring organs, which disrupt tubal peristalsis and make it impossible for the egg to move and be fertilized. Past infections (pelvic inflammatory disease, chlamydial infection and other sexually transmitted infections), infections after abortion, ectopic pregnancy, operations in the area of ​​the small pelvis, etc. can lead to tubal sterility. Diseases of the cervix that affect fertility are divided into anatomical and functional. Anatomical problems include conization of the cervix, stenosis of the cervical canal, congenital malformations, etc., and functional problems are related to changes in the cervical mucus. Diseases of the uterus lead to sterility by two mechanisms. The first is associated with space-occupying processes such as uterine fibroids, adhesions, polyps, preventing the implantation of the fertilized ovum, and the second, congenital anomalies of the uterus (hypoplastic uterus, bicornuate, unicornuate, septate uterus), leading to a reduced volume of the uterine cavity and inability to fetal development. Another common cause of infertility in women is endometriosis, which is characterized by the spread of endometrial lining outside the uterine cavity – in fallopian tubes, ovaries, abdominal organs, etc. The etiology of endometriosis is not fully understood, but it is certain that 40 to 50% of women with endometriosis suffer from infertility. The causes of infertility in women are extremely diverse. In the next part of the article, we will consider methods of diagnosis and treatment of the various causes of infertility. Bibliography 1. Gynecology edited by Prof. Dr. Angel Dimitrov, MD, PhD. and Prof. Dr. Viktor Zlatkov, MD. 2. Female Infertility – StatPearls – NCBI Bookshelf (nih.gov) 3. Causes and Prevalence of Factors Causing Infertility in a Public Health Facility (nih.gov) 4. Infertility (who.int)are divided into anatomical and functional. Anatomical problems include conization of the cervix, stenosis of the cervical canal, congenital malformations, etc., and functional problems are related to changes in the cervical mucus. Diseases of the uterus lead to sterility by two mechanisms. The first is associated with space-occupying processes such as uterine fibroids, adhesions, polyps, preventing the implantation of the fertilized ovum, and the second, congenital anomalies of the uterus (hypoplastic uterus, bicornuate, unicornuate, septate uterus), leading to a reduced volume of the uterine cavity and inability to fetal development. Another common cause of infertility in women is endometriosis, which is characterized by the spread of endometrial lining outside the uterine cavity – in fallopian tubes, ovaries, abdominal organs, etc. The etiology of endometriosis is not fully understood, but it is certain that 40 to 50% of women with endometriosis suffer from infertility. The causes of infertility in women are extremely diverse. In the next part of the article, we will consider methods of diagnosis and treatment of the various causes of infertility. Bibliography 1. Gynecology edited by Prof. Dr. Angel Dimitrov, MD, PhD. and Prof. Dr. Viktor Zlatkov, MD. 2. Female Infertility – StatPearls – NCBI Bookshelf (nih.gov) 3. Causes and Prevalence of Factors Causing Infertility in a Public Health Facility (nih.gov) 4. Infertility (who.int)are divided into anatomical and functional. Anatomical problems include conization of the cervix, stenosis of the cervical canal, congenital malformations, etc., and functional problems are related to changes in the cervical mucus. Diseases of the uterus lead to sterility by two mechanisms. The first is associated with space-occupying processes such as uterine fibroids, adhesions, polyps, preventing the implantation of the fertilized ovum, and the second, congenital anomalies of the uterus (hypoplastic uterus, bicornuate, unicornuate, septate uterus), leading to a reduced volume of the uterine cavity and inability to fetal development. Another common cause of infertility in women is endometriosis, which is characterized by the spread of endometrial lining outside the uterine cavity – in fallopian tubes, ovaries, abdominal organs, etc. The etiology of endometriosis is not fully understood, but it is certain that 40 to 50% of women with endometriosis suffer from infertility. The causes of infertility in women are extremely diverse. In the next part of the article, we will consider methods of diagnosis and treatment of the various causes of infertility. Bibliography 1. Gynecology edited by Prof. Dr. Angel Dimitrov, MD, PhD. and Prof. Dr. Viktor Zlatkov, MD. 2. Female Infertility – StatPearls – NCBI Bookshelf (nih.gov) 3. Causes and Prevalence of Factors Causing Infertility in a Public Health Facility (nih.gov) 4. Infertility (who.int)