From Oocyte to Blastocyst: A Comparison of IVF Embryo Attrition Rates Based on Ovarian Reserve

Objectives The effect of ovarian reserve on expected in vitro fertilisation (IVF) attrition remains controversial. This study analyses IVF attrition rates based on ovarian reserve and stimulation protocol to create customised pre-treatment counselling tools for assisting clinicians in setting accurate patient expectations. Material and Methods We completed a retrospective chart review of 18–44-year-old patients who underwent IVF treatment at a single academic institution between January 1, 2013, and March 23, 2023. Cycle outcomes, number of retrieved oocytes, mature oocytes, fertilised embryos, and blastocysts were analysed for patients with polycystic ovary syndrome (PCOS), unexplained infertility, and diminished ovarian reserve (DOR). A Poisson regression model was used to compare oocyte maturation, fertilisation, and blastulation rates among groups, adjusted for age, body mass index, race, and insemination method. Results Three hundred and thirteen couples underwent a total of 385 IVF cycles analysed in this study. There were 109 patients who underwent 120 cycles in the unexplained infertility group (31% cycles), 133 patients with 143 cycles in the PCOS group (37% cycles), 40 patients with 45 cycles in the DOR antagonist stimulation group (12% cycles), and 39 patients with 77 cycles in the DOR minimal stimulation group (20% cycles). No differences in oocyte maturation, fertilisation, or blastulation rate were seen among PCOS or DOR antagonist cycle groups when compared to unexplained infertility. After adjusting for confounders, blastulation rate was higher for the DOR minimal stimulation group compared to unexplained infertility (1.37-fold change, p = 0.04). Conclusion Rates of oocyte maturation, fertilisation, and blastulation were similar among all antagonist protocol cycles regardless of ovarian reserve. However, patients with DOR who undergo minimal stimulation may have modestly higher blastulation rates compared to DOR patients who undergo the antagonist protocol.