Letrozole Versus Chinese Herbal Medicine on Polycystic Ovary Syndrome (PCOS)

Inclusion criteria 1. Chinese women with PCOS. PCOS must have been diagnosed based on the presence of two of the following three Rotterdam criteria : (1) oligomenorrhea, anovulation; (2) hyperandrogenism; and (3) the observation of polycystic ovaries by sonography. Oligomenorrhea is defined as an intermenstrual interval \>35 days or \<8 menstrual bleedings in the past year. Amenorrhea is defined as an intermenstrual interval \>90 days. 2. History of at least one year of infertility. 3. Age between 20 and 40 years old. 4. Normal semen analysis based on World Health Organization criteria (2010). The husband did not need to sign the consent form because semen analysis is part of the clinical assessment at the sites. A sperm concentration ≥15 × 106/mL and total motility ≥40% in the semen analysis of the husband was required for the woman to be included. 5. Normal uterine cavity and at least one tube patent upon hysterosalpingography or HyCoSy. Exclusion criteria 1. History of significant system diseases such as heart, lung, or kidney diseases. 2. History of other endocrine disorders. 3. Use of hormonal therapy, including metformin, in the past 3 months. 4. Previous sterilization procedures (vasectomy or tubal ligation) that have been reversed.