Reducing the dose of human chorionic gonadotropin in high responders does not affect the outcomes of in vitro fertilization

Objective

The lowest effective hCG dose in high responders during IVF–embryo transfer (ET) has not been established. This study was performed to confirm that a dose of 3,300 IU is sufficient to provide adequate oocyte maturation and fertilization.

Design

Retrospective review of IVF clinical data.

Setting

Infertility center at a tertiary care university.

Patient(s)

Ninety-four IVF cycles were analyzed from high responders based on peak E₂ levels. Demographics were compared including age, diagnosis, and stimulation protocol.

Intervention(s)

On the day of hCG administration, if E₂ levels were ≥2,500 but <4,000 pg/mL, patients received 5,000 IU (group A). For levels between 4,000 pg/mL and 5,500 IU pg/mL, they received 3,300 IU (group B).

Main outcome measure(s)

Number of oocytes retrieved, proportion of mature oocytes, fertilization rates, chemical and clinical pregnancy rates (PR). The incidence and severity of ovarian hyperstimulation syndrome (OHSS) was also analyzed.

Result(s)

Mean ages were 35.4 ± 0.7 and 33.2 ± 0.7 for groups A and B, respectively. Peak E₂ levels differed significantly (2,907 ± 76 vs. 4,260 ± 129 pg/mL), as well as the mean number of eggs retrieved (15.9 ± 0.9 vs. 20.3 ± 1.2). Proportion of mature eggs (81.6% vs. 81.9%), fertilization rate (70.5% vs. 68.7%), chemical PR (58.7% vs. 58.7%), and clinical PR (50.0% vs. 43.5%) were similar. There was no difference in the incidence of mild, moderate, or severe OHSS.

Conclusion(s)

A reduced hCG dose of 3,300 IU results in a similar proportion of mature eggs, similar fertilization rates, and similar PRs compared to 5,000 IU. Reducing the dose of hCG does not eliminate the risk of OHSS in a high-risk group.

Key words:  IVF , embryo transfer , hCG dose , controlled ovarian hyperstimulation , fertilization , oocyte , implantation rate , pregnancy rate , ovarian hyperstimulation syndrome