Sliding scale HCG trigger yields equivalent pregnancy outcomes and reduces ovarian hyperstimulation syndrome: Analysis of 10,427 IVF-ICSI cycles

OBJECTIVE To evaluate pregnancy outcomes and the incidence of ovarian hyperstimulation syndrome (OHSS) using a sliding scale hCG protocol to trigger oocyte maturity and establish a threshold level of serum b-hCG associated with optimal oocyte maturity. DESIGN Retrospective cohort. SETTING Academic medical center. PATIENTS Fresh IVF cycles from 9/2004-12/2011. INTERVENTION 10,427 fresh IVF-ICSI cycles met inclusion criteria. hCG was administered according to E2 level at trigger: 10,000IU vs. 5,000IU vs. 4,000IU vs. 3,300IU vs. dual trigger (2mg leuprolide acetate + 1,500IU hCG). Serum absorption of hCG was assessed according to dose and BMI. MAIN OUTCOME MEASURES Oocyte maturity was analyzed according to post-trigger serum b-hCG. Fertilization, clinical pregnancy, live birth and OHSS rates were examined by hCG trigger dose. RESULTS Post-trigger serum b-hCG 20-30, 30-40, and 40-50 mIU/mL was associated with reduced oocyte maturity as compared b-hCG >50 (67.8% vs. 71.4% vs. 73.3% vs. 78.9%, respectively, P<0.05). b-hCG 20-50 mIU/mL was associated with a 40.1% reduction in live birth (OR 0.59, 95% CI 0.41-0.87). No differences in IVF outcomes per retrieval were seen for varying doses of hCG or dual trigger when controlling for patient age. The incidence of moderate to severe OHSS was 0.13% (n = 14) and severe OHSS was 0.03% (n = 4) of cycles. CONCLUSIONS Moderate stimulation with sliding scale hCG at trigger and fresh transfer is associated with low rates of OHSS and favorable pregnancy rates. Doses as low as 3,300IU alone or dual trigger with 1,500IU are sufficient to facilitate oocyte maturity.