OBJECTIVE: To determine if an association exists between HCG serum level after injection and oocyte maturation in IVF/ICSI patients. DESIGN: Retrospective cohort study MATERIALS AND METHODS: Charts were reviewed from patients ≤35 years undergoing IVF/ICSI for male factor infertility from 2004-2009. Ovarian follicles were stimulated with gonadotropins until urinary HCG (uHCG) intramuscular injection. 10,000, 5,000, 4,000, or 3,300 IU uHCG was injected 36 hours prior to oocyte retrieval according to peak estradiol (E2) levels with ≥3 follicles of ≥17mm in mean diameter. Serum for E2 and HCG was collected 8-10 hours later. RESULTS: Table 1 shows findings by uHCG dose. Age and body mass index (BMI) did not differ across groups. Total gonadotropin dose and day 3 FSH was higher, and E2 was lower in the 10,000 IU group (p=0.02, p<0.001, p<0.001, respectively). Serum HCG after injection ranged from 5-1092 mIU/ml and was higher in the 10,000 IU group, p<0.001. Percent mature oocytes and clinical pregnancy rates were similar across groups.Table 1Oocyte maturity by uHCG doseuHCG dose (IU)10,000 (n=183)5,000 (n=153)4,000 (n=150)3,300 (n=90)P valueAge (years)31 ± 331 ± 430 ± 430 ± 4NSBMI (kg/m2)23 ± 723 ± 722 ± 622 ± 7NSD3 FSH (mIU/ml)4.3 ± 23.8 ± 23.6 ± 23.4 ± 20.02Total gonadotropin dose (IU)2420 ± 14601981 ± 9301787 ± 13891490 ± 642<0.001E2 (pg/ml) after HCG1558 ± 5422493 ± 7802983 ± 6793563 ± 776<0.001Serum HCG (mIU/ml)235 ± 136167 ± 102141 ± 87141 ± 89<0.001% Mature oocytes77% (1353/1764)75% (1528/2032)76% (1803/2375)78% (1102/1411)NSMean ± standard deviation. One-way ANOVA and Chi-square tests, p<0.05 Open table in a new tab Mean ± standard deviation. One-way ANOVA and Chi-square tests, p<0.05 CONCLUSIONS: uHCG dose and serum level after injection do not appear to impact oocyte maturation in young lean women undergoing IVF/ICSI for male factor infertility. Further studies in populations with poor ovarian reserve and higher BMI are warranted.