Different doses of letrozole combined sequentially as letrozole+urofollitropin for treating anovulatory infertility in patients with polycystic ovary syndrome: a pragmatic randomized controlled trial

INTERVENTION: Group A:2.5mg+FSH;GroupB:5.0mg+FSH; CONDITION: polycystic ovary syndrome PRIMARY OUTCOME: Ovulation rate;pregnancy rate;Clinical pregnancy rate;ongoing pregnancy rate; INCLUSION CRITERIA: (1) Patients with PCOS who meet the Rotterdam diagnostic criteria in 2003: (1) Patients with rare ovulation or even anovulation; (2) Clinical symptoms or biochemical manifestations of hyperandrogenism; (3) Abdominal ultrasound shows polycystic changes in the ovaries (vaginal ultrasound shows that one or even both ovaries contain more than 12 follicles with a diameter of 2‐9mm). Diagnosis can be made if two of the above three criteria are met. (2) Patients under 40 years old, with normal sexual activity and infertility for at least 1 year. (3) Hysterosalpingography shows normal uterine morphology and at least one patent fallopian tube. (4) The results of the spouse's semen analysis are normal or mildly oligoasthenozoospermia. (5) All organ functions are normal and there are no accompanying endocrine diseases such as pituitary dysfunction or hyperthyroidism. (6) The patient has been fully informed of the nature, significanc