Objective: To determine the effect of number of oocytes retrieved and number of 2PN embryos developed on in vitro fertilization (IVF) outcomes.
Design: Retrospective data analysis.
Setting: University practice.
Patient(s): Reproductive-aged women (n = 467).
Intervention(s): First fresh nondonor cycle of IVF.
Main outcome measure(s): Clinical pregnancy rate
Result(s): Clinical pregnancy rates increase until age 30 (odds ratio (OR) 1.72 per year (95% confidence interval 1.19-2.49)) before demonstrating a linear decline. In subjects < 37 years old, maximal clinical pregnancy rates are seen when 20 oocytes were retrieved (OR 1.03 (0.96-1.11)), five 2-pronuclei (2PN) embryos developed (OR 1.91 (1.29-2.87)), and no more than two embryos transferred (OR 0.72 (0.56-0.92) for each additional embryo transferred > 2). In subjects > or = 37 years old, maximum clinical pregnancy rates were achieved in subjects who had ten oocytes retrieved (OR 1.09 (1.01-1.18)), 20 2PN embryos developed (OR 1.29 (1.03-1.62)), and no more than two embryos transferred (OR 0.72 (0.56-0.92) for each additional embryo transferred > 2).
Conclusion(s): The odds of achieving a successful clinical pregnancy with IVF are greatest with retrieval of approximately 20 oocytes, transfer of no more than 2 embryos, and the development of about five 2PN embryos in women < 37 years old and ten 2PN embryos in women > or = 37 years old.