Human chorionic gonadotropin (hCG) and in vitro fertilization (IVF): postinjection serum levels do not predict outcome

Abstract

OBJECTIVE: hCG administration is required for final maturation of oocytes in an IVF cycle prior to retrieval. However, the serum hCG level required for successful IVF is unknown. We investigated if serum hCG levels the morning after the ovulatory injection of hCG (10, 000 units) correlate with (1) number of oocytes retrieved/follicle, (2) the maturity of the retrieved oocytes, (3) embryo quality, and/or (4) the incidence of pregnancy in patients undergoing in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI).DESIGN: Retrospective chart review.MATERIALS AND METHODS: Charts of 169 patients that underwent IVF with ICSI between 7/31/05–6/30/06 were reviewed. Patients were injected with hCG 34 hours prior to retrieval. Serum hCG was measured by chemiluminescent assay (Immulite 1000)® approximately 5.5 – 8.5 hours post hCG administration to ensure proper hCG administration. Patients with serum hCG values of zero were excluded from the study. Charts were reviewed to obtain the number of follicles on the day of hCG injection, number of oocytes retrieved, and number of oocytes with no Germinal Vesicle (mature). Embryo characteristics were ascertained for day 3 transfers (cell-number, embryo grade) or for day 5 transfers (Blastocyst stage and grade) using standard methods.RESULTS: Serum hCG levels averaged 202 ± 122 IU/L (range 35 – 623 IU/L). The percentage of oocytes retrieved per follicle and the percentage of mature oocytes did not vary with hCG level (89 ± 29% [r = 0.073, p > 0.05] and 89 ± 13% [r = 0.033, p > 0.05], respectively). For embryos transferred on day 3, there was no significant trend in the percentage of transferred embryos with 8 cells (53 ± 1.7%) or with A or A/B scores (73 ± 1.5%) over the entire range of hCG levels. For embryos transferred on day 5, there was no significant trend in the percentage of transferred embryos that were blastocysts (87 ± 1.5%) with no apparent trends in the distribution of blastocyst types. Additionally, for embryos transferred on day 5, blastocyst scores (predominantly A/A, A/B and B/B) occurred with the same prevalence (72 ± 2.9%), regardless of the hCG level. The incidence of clinical pregnancy (50%) was not associated with the hCG level (r = 0.088, p > 0.05) over the range of hCG levels seen.CONCLUSIONS: Serum hCG levels after ovulation induction did not correlate with oocytes retrieved/follicle, oocyte maturity, embryo quality, or the incidence of pregnancy. OBJECTIVE: hCG administration is required for final maturation of oocytes in an IVF cycle prior to retrieval. However, the serum hCG level required for successful IVF is unknown. We investigated if serum hCG levels the morning after the ovulatory injection of hCG (10, 000 units) correlate with (1) number of oocytes retrieved/follicle, (2) the maturity of the retrieved oocytes, (3) embryo quality, and/or (4) the incidence of pregnancy in patients undergoing in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective chart review. MATERIALS AND METHODS: Charts of 169 patients that underwent IVF with ICSI between 7/31/05–6/30/06 were reviewed. Patients were injected with hCG 34 hours prior to retrieval. Serum hCG was measured by chemiluminescent assay (Immulite 1000)® approximately 5.5 – 8.5 hours post hCG administration to ensure proper hCG administration. Patients with serum hCG values of zero were excluded from the study. Charts were reviewed to obtain the number of follicles on the day of hCG injection, number of oocytes retrieved, and number of oocytes with no Germinal Vesicle (mature). Embryo characteristics were ascertained for day 3 transfers (cell-number, embryo grade) or for day 5 transfers (Blastocyst stage and grade) using standard methods. RESULTS: Serum hCG levels averaged 202 ± 122 IU/L (range 35 – 623 IU/L). The percentage of oocytes retrieved per follicle and the percentage of mature oocytes did not vary with hCG level (89 ± 29% [r = 0.073, p > 0.05] and 89 ± 13% [r = 0.033, p > 0.05], respectively). For embryos transferred on day 3, there was no significant trend in the percentage of transferred embryos with 8 cells (53 ± 1.7%) or with A or A/B scores (73 ± 1.5%) over the entire range of hCG levels. For embryos transferred on day 5, there was no significant trend in the percentage of transferred embryos that were blastocysts (87 ± 1.5%) with no apparent trends in the distribution of blastocyst types. Additionally, for embryos transferred on day 5, blastocyst scores (predominantly A/A, A/B and B/B) occurred with the same prevalence (72 ± 2.9%), regardless of the hCG level. The incidence of clinical pregnancy (50%) was not associated with the hCG level (r = 0.088, p > 0.05) over the range of hCG levels seen. CONCLUSIONS: Serum hCG levels after ovulation induction did not correlate with oocytes retrieved/follicle, oocyte maturity, embryo quality, or the incidence of pregnancy.