Infertility is defined as a person who lives together after marriage, has a normal sexual life, without contraception for more than 1 year and fails to conceive. Every married couple carries the wonderful dream of conceiving a child of their own, which is indispensable for every healthy ordinary family, but infertility is a big blow to families. The lack of knowledge about infertility has led to many people not paying attention to it in the early stages, which eventually leads to infertility and infertility, a problem that is currently plaguing some families. Infertility is a complex disease caused by a variety of reasons, and a series of relevant examinations are needed before treatment, so that the cause of the disease can be clarified as much as possible, and thus the right treatment can be given. (1) Gynecological examination Gynecological examination is the most basic examination performed by obstetricians and gynecologists on each patient, mainly to examine the vagina, cervix, uterus, fallopian tubes, ovaries, parametrium and inner wall of pelvic cavity, and its main function is to make early diagnosis, prevention and early treatment of some gynecological diseases. The gynecological examination has its own special features, requiring the patient to remove one pant leg, including the underwear, and take a special position, and then with the help of some simple instruments to help the doctor understand some diseases of women’s sexual reproductive organs. In our country, most women are resistant to gynecological checkups and do not have the awareness and habit of going to the hospital for regular checkups. In fact, gynecological examination is not as terrible as people think, and it protects women’s health to a great extent. (2) Basal body temperature determination Basal body temperature (BBT), also known as resting body temperature, is the body temperature measured after 6 to 8 hours of sleep, for example, in the morning after waking up from a deep sleep, when the body temperature has not been affected by exercise, diet or emotional changes, and is usually the lowest body temperature of the body during the day and night. Basal body temperature is a commonly used non-invasive monitoring method that requires a sufficient amount of sleep for at least 6 hours and is measured before waking up and doing any activity. Under normal circumstances, the ovaries of women of reproductive age are dominated by the secretion of estrogen during the first half of menstruation and by the secretion of the corpus luteum after ovulation. The high temperature period will be maintained until the corpus luteum shrinks and menstruation begins. Therefore, with ovulation, the body temperature will be slightly elevated. Conversely, anovulatory menstruation lacks hormonal action and the basal body temperature does not have regular cyclic changes. Also, the length of the luteal phase can be used to assess the function of the ovaries. Generally speaking, a high temperature period should be more than 12 days before it is considered normal ovarian function. If the high temperature period is below 11 days, it is possible that the luteal function is inadequate and can assist in diagnosing the cause of menstrual disorders. Basal body temperature can be used to check the cause of infertility: Basal body temperature is measured to understand her ovarian function, the presence or absence of ovulation and luteal function. The basal body temperature can be used to determine ovulation to guide contraception and conception. Basal body temperature can also be measured to assist in the diagnosis of pregnancy. If a high basal body temperature persists for more than two weeks, consider going to the hospital for a check-up, as it is highly likely that you are pregnant. (3) Cervical mucus examination and scoring Cervical mucus is a hydrogel containing glycoproteins, plasma proteins, sodium chloride and water. The cervical mucus is thin and abundant during ovulation. The glycoproteins in the cervical mucus are arranged in a mesh, and near the time of ovulation, the mesh becomes larger under the influence of estrogen to be suitable for the passage of sperm. Under normal circumstances, crystals are visible in the mucus smear on the 8th to 10th day of the menstrual cycle. During ovulation, the estrogen level in the body reaches its peak and the smear appears as typical lambdoid crystals. After ovulation, the crystals gradually decrease and cease to appear by day 22. On day 22 of the menstrual cycle, the crystals turn into ellipsoidal bodies. This is often used clinically to predict ovulation and guide conception. It is more effective when combined with basal body temperature and vaginal exfoliation cell examination to predict ovulation and select the date of conception. If all the smears are ellipsoidal without amniotic crystals, it is indicative of pregnancy and can be used to diagnose early pregnancy and estimate the prognosis of early pregnancy. Cyclic changes in cervical mucus indicate good ovarian function and the cause of the lesion is in the uterus, which can assist in identifying the type of amenorrhea. (4) Vaginal cytology The degree of maturation of vaginal squamous epithelial cells is directly proportional to the level of estrogen in the body. The higher the level of estrogen, the more mature the differentiation of vaginal epithelial cells. Therefore, observation of the ratio of each cell layer of vaginal squamous epithelial cells can reflect the level of estrogen in the body, observe the secretion of female hormones, and understand the level of estrogen and progesterone and the function of the ovaries. (5) Hysterosalpingography Hysterosalpingography (HSG) has been used since the 1920s. It is performed by injecting a contrast agent into the uterine cavity through the cervical canal to form an obvious artificial contrast with the surrounding tissues under X-ray, so that the cavity can be visualized and the situation in the uterus and fallopian tubes can be understood. There are two types of contrast agents, iodized oil and iodinated water, depending on the contrast agent. Iodinated oil is the most commonly used because of its high density, clear visualization, low irritation and no abdominal pain. A hysterosalpingogram is needed in infertile patients to understand the morphology of the uterus, the size of the uterine cavity, bilateral tubal patency and the condition of the pelvic cavity. This test is safe, does not require anesthesia, is less invasive, is painless and has some therapeutic effects, so it is more acceptable to the patient. Patients who are suitable for hysterosalpingography ①Patients with primary or secondary infertility and suspected tubal obstruction. ②History of previous abdominal surgery. ③Observation of uterine morphology to determine the presence of uterine malformations and their types, the presence of uterine adhesions, submucosal fibroids, endometrial polyps and foreign bodies. ④In case of multiple mid-trimester spontaneous abortions and suspected incomplete atresia of the endocervix, observe the relaxation of the endocervix during non-pregnancy. Preparation before imaging: ① Choose the time of hysterosalpingography from 3 days after menstruation to before ovulation, i.e. between the 7th day ± 4 days of the menstrual cycle. If the time is too early, the endometrium of the uterine cavity may still be traumatized and the contrast agent may enter the peri-uterine blood vessels from the endometrium trauma, causing pulmonary embolism or squeezing the remaining endometrial debris in the uterine cavity into the pelvis, artificially causing endometriosis. After ovulation, then the endometrium has thickened significantly, and the thickened endometrium may cover the fallopian tube mouth at the entrance of the fallopian tube causing the illusion of obstruction. At the same time, endometrial debris is shed during the secretory phase, blocking the entrance of the fallopian tubes or being squeezed into the pelvis causing endometriosis. The fertilized fertilized egg may also be squeezed into the fallopian tube, causing ectopic pregnancy. (ii) Those without acute or subacute pelvic inflammatory disease and with a body temperature of 37.5°C or less. (③Leukostasis suspension examination shows no trichomonas or mycobacterial infection in the vagina. ④No sexual intercourse and deep water bathing for 3 weeks before and 2 weeks after the imaging to prevent infection. Infertile patients who are not suitable for hysterosalpingography: ①Iodine allergy. ②Patients who are in pregnancy or menstrual period. ③Postpartum, miscarriage, or within 6 weeks after curettage. ④Acute and subacute internal and external genital inflammation. ⑤Serious systemic diseases that cannot tolerate surgery. (6) Endometrial scraping: for infertility, scraping should be performed before menstruation or within 12 hours of menstruation in order to determine whether there is ovulation. Endometrial scraping should also be performed for suspected endometrial tuberculosis and sent for pathological examination. In cases of prolonged and heavy bleeding due to residual uterine cavity after abortion or incomplete shedding of endometrium, scraping is not only diagnostic but also therapeutic. (6) Endocrine examination The endocrine system is the general controller of the body, and through the regulation of hormone secretion, the system controls the overall function of the body. The endocrine disorders caused by various reasons can lead to a series of diseases and damage women’s physical and mental health. Hormone levels play a crucial role in women’s reproductive health. In many cases, it is the hormonal changes that lead to changes in the female body itself and cause various diseases, such as adolescent gynecomastia, polycystic ovary syndrome, amenorrhea and lactation syndrome. Sex hormone levels are measured to understand female endocrine function and to diagnose diseases related to endocrine disorders. The 6 commonly used sex hormones, namely folliculogenic hormone (FSH), luteinizing hormone (LH), estradiol (E2), progesterone (P), testosterone (T), and prolactin (PRL), basically satisfy the clinician’s screening for endocrine disorders and general understanding of physiological functions. The best time to check the basal function of the ovaries is on the 3rd to 5th day after menstruation, which is the early follicular period and can reflect the functional status of the ovaries. However, for those who have not had a period for a long time and are anxious to know the results of the examination, the examination can be done at any time, and this time will be the premenstrual period by default, and the results will refer to the luteal phase examination. Hormone levels can also be checked at different times of menstruation to make a comprehensive judgment. In addition to the examination of sex hormones, the examination of thyroid hormones is also required. (7) Gynecological ultrasound Ultrasound examination is painless and non-invasive, making it one of the most relaxing examinations. The purpose of gynecological ultrasound examination is mainly to monitor follicular development and also to check for abnormalities in the development of reproductive organs, such as the presence of uterine tumors, endometriosis, congenital uterus, abnormal vaginal development, ovarian masses, fluid in the fallopian tubes, inflammatory masses or abscesses in the pelvis, etc. Gynecologic ultrasound includes abdominal ultrasound and vaginal ultrasound. Abdominal ultrasound places the ultrasound probe in the lower abdomen to observe the pelvic cavity, focusing on the uterus, adnexa and pelvis. You will need to drink water and hold urine to the maximum before the exam. Vaginal ultrasound involves inserting the probe into the vagina for examination, focusing on the cervix and endometrium. This method does not require holding urine and has more accurate results due to the proximity to the uterus and ovaries and the clear resolution of the images. It is not suitable for people with vaginal bleeding and infectious diseases. (8) Immunological examination including anti-sperm antibodies, anti-ovarian antibodies, anti-hyaline antibody, anti-endometrial antibody, etc. The normal organism has autoimmune regulation function and produces very weak autoantibodies to help clear the aging degenerated self components in the body. Once the immune system produces excessive immune response to its own tissues for some reason, an overpowering series of immune reactions will occur, resulting in an increase of immune active cells in the invaded tissues and deposition of immune complexes, which will lead to functional changes. Sperm are antigenic and can induce specific anti-sperm antibodies under certain conditions. The presence of anti-sperm antibodies in the serum and/or seminal plasma of some infertile men and in the serum and/or cervical mucus of women has been detected by immunological methods in men and women with unexplained infertility. Therefore, anti-sperm antibodies are now recognized as an important cause of immune infertility. Anti-ovarian antibodies are produced in certain patients with autoimmune diseases and are directed against their own ovarian components, which can lead to premature ovarian failure, etc. Zona pellucida is a clear, membranous protective layer that forms around the ovum during oogenesis. It can play an important role in inducing the sperm acrosome reaction, sperm-egg recognition, binding, penetration and organization of multiple sperm into the egg. Anti-hyaloid antibodies can block sperm-egg binding and interfere with implantation, leading to infertility. Anti-endometrial antibodies arise in two ways: on the one hand because of ectopic endometrial stimulation of the system, and on the other hand because of a malfunction of the body’s immune system (autoimmune deficiency). When such anti-endometrial antibodies are produced in large quantities to a certain level due to repeated stimulation, they can react with their own endometrial tissue in an antigen-antibody binding reaction and activate the immune system to cause damaging effects, resulting in damage to the biochemical metabolism and physiological functions of endometrial tissue cells, interfering with and preventing sperm-egg union, fertilization of the egg and development of the embryo sac, leading to infertility or miscarriage. (9) Chromosome examination There are 46 chromosomes in human somatic cells, which are paired with each other. Of these, 22 pairs are autosomes and 1 pair is a sex chromosome. There is no sex difference in autosomes, while sex chromosomes differ between men and women. In females, the 2 sex chromosomes are morphologically identical and are called XX chromosomes; in males, the 2 sex chromosomes are not identical and are X and Y chromosomes. Some infertility cases are due to sex chromosome abnormalities, which can be identified by chromosome culture. Chromosomal examination is mainly indicated for patients with primary amenorrhea, premature ovarian failure, secondary amenorrhea, miscarriage and habitual abortion. (10) Eugenics 4 tests Eugenics 4 tests include rubella virus, cytomegalovirus and toxoplasmosis virus to prevent pregnant women from contracting viruses in early pregnancy, which may lead to miscarriage or fetal malformation. 2.Examinations to be done on the male side (1) Male examination Observe the development of the male penis, scrotum, testicles, epididymis and vas deferens. Anal examination mainly examines the prostate and seminal vesicles, massage out the prostate fluid for laboratory examination if necessary. (2) Routine semen examination Semen analysis is an important basis for male fertility assessment. It can observe the color, odor, semen volume, viscosity, liquefaction time, pH, total sperm count, sperm density, sperm motility, sperm morphology, sperm survival rate, presence of white blood cells, etc. ①Semen traits: normal semen is gray or milky white, light yellow is seen in those with long intervals of semen discharge, brownish red is seen in seminal vesicle inflammation, seminal vesicle tumors, prostate inflammation, and occasionally in urethral stones. The smell of semen is similar to the special fishy smell of carob or chestnut flowers. The freshly ejaculated semen is thick and jelly-like, and then liquefies into a thin liquid after about 3 to 30 minutes. Semen that does not solidify is seen in congenital bilateral vas deferens with seminal vesicle agenesis. Semen that does not liquefy in more than 30 minutes is seen in patients with prostate and seminal vesicle disease. Increased viscosity of semen is seen in malfunctioning secretion of the liquefaction enzyme system of the prostate. The normal semen volume is about 2-6 ml, with an average volume of 3 ml. Less than 1 ml or more than 8 ml is considered abnormal. A decrease in semen volume is seen in prostate and seminal vesicle lesions or retrograde ejaculation. The normal pH of semen is 7.0-7.8. When semen is acidic, sperm activity and metabolism level decreases, when semen is alkaline, sperm motility increases, but when alkalinity is too strong, it decreases again. Sperm density: Sperm density refers to the number of sperm contained in each milliliter of semen detected by counting methods. The total number of sperm refers to the total amount of sperm in the semen discharged by each ejaculation. Normal sperm density is 20 to 200 (109/ml). (3) Prostate fluid examination Observe the prostate for inflammation and trichomonas infection. The biochemical composition of the prostate fluid can be measured to understand the physiological activity, metabolic status and pathological changes of the gland. (4) Endocrine examination Including the determination of sex hormone levels, the same items as the female examination. (5) Immunological examination Anti-sperm antibodies can be produced during surgery, trauma and infection in men, which have an effect on the production and vitality of sperm. The higher the concentration of anti-sperm antibodies, the longer the time needed for conception. (6) Vasectomy and seminal vesiculography It is suitable for patients with normal testicular morphology, size and texture, but low sperm count in semen or azoospermia; patients with no abnormal epididymis and basically normal spermatogenesis on testicular biopsy; patients with normal blood FSH and normal physical examination; patients with weak ejaculation or pain during orgasm and suspected obstruction of the vas deferens. (7) Ultrasound Prostatic hyperplasia, syringomyelia, testicular tumors, etc. can be observed. (8) Testicular biopsy For male infertility with normal testicular volume and hormone level; unexplained oligospermia (less than 10 million/ml); azoospermia. (9) Chromosome examination When the total number of spermatozoa in each ejaculate is less than 20 million and the testicular volume is equal to or less than 10 ml, sex chromatin and karyotype identification should be done. The above are the examinations required before treating infertility, and the items and order of the examinations can be arranged according to individual conditions in order to clarify the causes of infertility so that more effective treatments can be taken.