Oocyte maturation employing a GnRH agonist in combination with low-dose hCG luteal rescue minimizes the severity of ovarian hyperstimulation syndrome while maintaining excellent pregnancy rates.

BACKGROUND: The traditional hCG 'trigger' for initiating final oocyte maturation exacerbates ovarian hyperstimulation syndrome (OHSS) in patients with an excessive follicular response because of its sustained stimulatory effect on the corpora lutea. However, a GnRH agonist trigger can produce a short duration endogenous LH surge which is adequate to initiate oocyte maturation, but allows the corpora lutea to regress, reducing the severity of OHSS. This approach produces an excellent embryology outcome, but generally results in low pregnancy rates even with the early initiation of estrogen and progesterone luteal support. The purpose of this study was to determine if a low dose of hCG (1500 IU) support on the day of oocyte retrieval can maintain good pregnancy rates, while not abolishing the protective effect of an agonist trigger on the development of severe OHSS.

METHODS: This retrospective study included 71 women who were at high risk of severe OHSS (≥ 14 follicles ≥ 12 mm) and who received an agonist trigger for final oocyte maturation.

RESULTS: The transfer of a solitary embryo produced a biochemical pregnancy rate of 60.6% and a clinical ongoing pregnancy rate of 52.1%. Only one patient was hospitalized with severe OHSS (1.4%), despite the average patient producing nearly 17 oocytes per cycle.

CONCLUSIONS: Oocyte maturation employing a GnRH agonist (protocol) in combination with low-dose hCG luteal support produces excellent clinical pregnancy rates, while not compromising the ability of GnRH agonist to prevent severe OHSS.