Prolongation of the follicular phase in in vitro fertilization results in a lower ongoing pregnancy rate in cycles stimulated with recombinant follicle-stimulating hormone and gonadotropin-releasing hormone antagonists☆

Abstract 

Objective

To assess the effect of altering the timing of hCG administration on ongoing pregnancy rates in patients stimulated with recombinant FSH (rec-FSH) and GnRH antagonists for IVF.

Design

Prospective, randomized, controlled trial.

Setting

Tertiary referral center.

Patient(s)

Four hundred thirteen patients undergoing IVF.

Intervention(s)

Rec-FSH stimulation starting on day 2 of the cycle combined with daily GnRH antagonist starting on day 6 of stimulation. Patients were randomized to receive 10,000 IU of hCG either as soon as at least three follicles were ≥17 mm on ultrasound (early-hCG group, 208 patients) or 2 days later after this criterion was met (late-hCG group, 205 patients).

Main outcome measure(s)

Ongoing pregnancy rate.

Result(s)

Fertilization rates and number and quality of embryos transferred did not differ between the two groups. However, a significantly lower ongoing pregnancy rate was present in the late-hCG as compared with the early-hCG group (25.0% vs. 35.6%, respectively).

Conclusion(s)

Prolongation of the follicular phase in patients stimulated with rec-FSH and GnRH antagonists for IVF does not affect oocyte or embryo quality but is associated with a significantly lower ongoing pregnancy rate.

Keywords:  GnRH antagonists, recombinant FSH, human chorionic gonadotropin