Aromatase inhibitors plus HMG for infertile PCOS women Prof.Xiangyan RUAN (1,2), MD. PhD. 1 Beijing Obstetrics & Gynecology Hospital,Capital Medical University, China 2 University Women's Hospital of Tuebingen, Germany PCOS affects 6 – 9% of women of all races worldwide (using strict criteria) and 15% (using broad criteria).Causes 75% of anovulation related infertility Treatment strategies for PCOS:Life style adjustment, rational exercise and nutrient preparation;treatment of hyperandrogenism (hyperandrogenemia and clinical signs); treatment of menstrual disorders; treatment of insulin resistance; Improvement of fertility (for women who want pregnancy). Treatment of PCOS women with fertility requests Treatment objective: Ovulation Induction non-ovulatory patients, and then achieve the normal pregnancy; Basic therapy:Nutrient preparation 3 months before the pregnancy. Ovulation Induction:First-line treatment,Second-line treatment,In vitro fertilization-embryo transplantation (IVF-ET) Clomiphene citrate (CC) is the traditional first-line treatment for chronic anovulation of PCOS. But 20%~25% of PCOS women fail to ovulate with incremental doses of CC, no clear concensus exists about the treatiment for CC-resistance.for this reason,our center (everyday more than 500 outpatients and 50% of them are PCOS patients.We use letrozole (LTZ)combined Hp-HMG in CC-resistant infertile women with PCOS under at least three months pretreatment and got high clinic pregnancy rate(more than 35%/cycle), lower multiple pregnancy rate (2.9%) Lower early abortion rate( 6 % )and lower ectopic pregnancy rate (2.2%). No OHSS occurred. CONCLUSION:Letrozole combined low dose Hp-HMG may be an effective and safe choice for reducing hyperstimulation and increasing pregnancy rate for ovulation induction in CC-resistant women with PCOS after at least three month pretreatment.