I. Diagnostic criteria for PCOS Fulfillment of at least two of the three: 1. Prolonged anovulation; 2. Hyperandrogenemia (clinical or biological); 3. Polycystic ovarian pattern. Among them, the level of antimuscarinic hormone >5 ng/ml can be used as an alternative diagnostic index for PCOM. II.Neuroendocrine abnormalities in patients with PCOS In patients with PCOS, gonadotropin-releasing hormone is released in a sustained rapid rhythmic release, and GnRH results in a stronger release of luteinizing hormone than follicle-stimulating hormone.Excessive release of LH leads to increased release of androgens, while a relative lack of FSH results in anovulation. Metformin improves the rhythm of LH release, suggesting that insulin resistance plays a role in the pathogenesis of PCOS. Hypomenorrhea or hypoovulation in patients with PCOS can be identified by menstrual irregularities. Irregular menstruation can present in a variety of ways, either by menopause or by excessive menstruation. A mid-luteal progesterone level of >0.3 ng/ml can determine that ovulation has occurred, but is also associated with abnormal follicle formation and infertility. If abnormal endometrial bleeding occurs, it is associated with endometrial hyperplasia and endometrial cancer. The following factors associated with infertility can elevate the risk during pregnancy: abnormal glucose tolerance (leading to gestational diabetes mellitus); hypertension (leading to placental abruption, pre-eclampsia, and preterm labor); obesity (leading to the complications mentioned above and rendering ovulation induction therapy less effective); and multiple pregnancies secondary to ovulation induction/IVF therapy. In terms of neonatal risk, pregnancy in infertile patients increases neonatal ICU hospitalization (OR 2.3) and perinatal mortality (OR 3.1), but has no effect on neonatal malformations. Current statistics indicate that >70% of women presenting with anovulatory infertility are due to PCOS, but 20% of PCOS patients have normal menstruation. In addition, 10% of infertility is due to oligospermia or reduced sperm motility in men. Ovarian Tubography found that 5% of infertility patients are due to bilateral blockage of fallopian tubes in women. Fourth, the treatment of anovulatory infertility 1, weight loss. 2, insulin sensitizer: metformin monotherapy can improve the pregnancy rate, but can not improve the fetal survival rate, metformin combined with clomiphene can improve the fetal survival rate of obese patients with BMI>35kg/m2, and thiazolidinediones are classified as pregnancy class C drugs because of side effects. 3, clomiphene citrate: clomiphene is a selective estrogen receptor modulator, which can stimulate the hypothalamus to secrete GnRH by inhibiting the negative feedback effect of estrogen, thus stimulating the release of FSH, and then promote follicle formation. after 6 treatment cycles, the rate of ovulation was 49%, the rate of pregnancy was 30%, and the rate of live-born production was 23%. A more recent RCT showed a pregnancy rate of 16% per cycle, 41% overall over three cycles, and a live-fetus production rate of 36%. The difference between pregnancy rates and live birth survival stems from the side effects of estrogen inhibitors. The anti-estrogenic effect leads to thinning of the uterine lining and a reduction in uterine mucus, and continued accumulation of the drug causes the anti-estrogenic effect to persist. 4, aromatase inhibitors: it can inhibit estradiol, stimulate the release of GnRH and FSH, letrozole does not have anti-estrogenic effect, its half-life is 45 hours, the dosage cycle of 3~5 days, 5 mg per day. the study found that letrozole treatment group of fetal malformations and chromosomal aberrations were lower than the incidence of clomiphene treatment group. 5. Gonadotropins: Low-dose FSH has been used as a first-line treatment measure. Recombinant FSH was given at 50-75 u daily for 5-7 days per cycle. the average pregnancy rate was 26% per cycle and 56% overall in 3 cycles of treatment, with the first cycle exceeding 28%. The live birth rate was over 50% and the multiple birth rate was less than 3%.