Conditions that need to be met for a normal pregnancy Female: 1. Normal ovulation function: women of childbearing age with normal ovarian function and normal regulation of other endocrine hormones can only produce mature eggs. 2. Normal fallopian tube function: The fallopian tube is open, the umbilical end picks up the egg into the fallopian tube and transports it to the abdomen of the fallopian tube to wait for the arrival of the sperm. The sperm-egg unites to form a fertilized egg, which begins to divide and form a mulberry ball, and is delivered to the uterus. 3. The endometrium is normal and synchronized with the development of the fertilized egg: the endometrium must be free from serious damage and some changes will occur in the endometrium after ovulation to form a membrane. At this time, the mulberry balls form a blastocyst and are ready to invade the membrane. The membrane and the blastocyst interact with each other, and the blastocyst continues to develop and gradually forms an early embryo. 4. Tolerance of the embryo by the maternal immune system: immune tolerance. This is manifested by the maternal body allowing the foreign body, i.e. this newly formed embryo, to remain in the uterus without being rejected. If the immune system is abnormally regulated, the pregnancy cannot continue. The mechanism of this process is complex and there are still many things that we cannot understand. 5. Adaptive changes in other maternal systems to meet the developmental needs of the embryo after pregnancy. Male partner: Simply put, the male partner has to provide quality sperm with the ability to fertilize. Let’s be more specific. 1, The male partner’s testicles should be able to produce high quality sperm that can enter the female vagina with the ejaculate. 2.Sperm change, move quickly, pass through the uterine cavity and enter the fallopian tube. 3. The sperm should be available in a certain number. Only with a large force working together can one lucky sperm and egg unite to form a fertilized egg. A normal pregnancy is only possible if both the man and the woman meet the above basic conditions. Among them, the ovulation function of the female ovary and the sperm production function of the male testis are the key among the key. The female partner usually ovulates once in a menstrual cycle, so she has one chance of pregnancy in a menstrual cycle. In contrast, the male partner’s sperm is produced continuously and uninterruptedly without cycles. Nowadays, IVF in the general sense is still inseparable from the female partner’s eggs and the male partner’s sperm. Common causes of infertility a. Female causes 1. Ovarian ovulatory dysfunction. Such as decreased ovarian function, ovarian failure, adhesions around the ovaries (pelvic inflammatory disease, pelvic tuberculosis, endometriosis, etc.), ovarian tumors, pituitary diseases such as pituitary tumors, hypothalamic diseases, insulin resistance, obesity, excessive wasting, PCOS, adrenal diseases, thyroid diseases, etc.; endocrine hormone secretion, function, regulation and other disorders occur in any part of the process. 2. Abnormalities in the function of the fallopian tubes caused by diseases in and around the fallopian tubes. Tubal obstruction, effusion, adhesions around the fallopian tubes (endometriosis, pelvic inflammatory disease, pelvic adhesions, etc.), tubal tract cysts, tubal agenesis, pelvic tuberculosis, etc. 3. Local abnormalities of the uterus. Such as cervical adhesions, cervical adhesions, cervical fibroids, cervical polyps, damaged endometrium, uterine fibroids, uterine sarcoma, uterine adenomyosis, uterine adenomyoma, endometrial polyps, uterine longitudinal septum, residual foreign bodies in the uterus (incomplete abortion, placental residue, fetal bone residue, embedded and residual birth control ring, etc.), cervicitis, endometritis, etc. 4. Localized vaginal lesions. Congenital abnormal development of vagina or congenital absence of vagina, such as longitudinal septum, oblique septum, vaginal atresia, no vagina and other congenital developmental abnormalities that affect sex life; acquired factors that cause narrowing of vagina, swelling in vagina, etc. Other factors, such as genetic factors, abnormalities in the immune system and immune diseases, hypercoagulable state of the blood system, endometriosis, etc., can also affect the fertility of women. Second, the male side causes 1, testicular sperm production disorders and semen discharge obstruction. Such as oligospermia, weak sperm, deformed sperm, azoospermia, retrograde ejaculation, prostate inflammation, cryptorchidism, testicular inflammation, testicular tumor, endocrine disorders, etc. Diseases of the thyroid gland, adrenal gland, etc. 2, male sexual dysfunction, varicocele, etc. 3, immune and genetic factors cause abnormal semen quality, thus ultimately affecting the fertilization ability of sperm. The reasons for both male and female lack of sexual knowledge; no or lack of normal sex life; insufficient frequency of sex life and other factors. To sum up, infertility refers to a couple having a normal sexual life without contraception for 1 year, and the female partner fails to have a clinical pregnancy. Infertility is not a disease, but a result of having multiple causes that are tried out. If a couple has not lived together with normal sexual intercourse for 1 year, infertility at this time cannot be called infertility. Because of the complexity of the causes of infertility and the need to find the causes from both men and women, diagnosis and treatment are time-consuming and costly.