clinics had more male infertility, were older and had higher BMIs than those in routine ICSI clinics. CONCLUSIONS: Performing routine ICSI for the purpose of improving fertilization rates leads to an overall decrease in birth rate. This decrease in success rates was seen in all age strata (data not shown).

Background: To evaluate the association of patient and IVF cycle characteristics with blastulation rate and formation of high-quality blastocysts Results: We analyzed autologous blastocyst cycles from 2013 to 2017. Cycles were subdivided into low (< 33%), intermediate (33-66%), and high (> 66%) blastulation rates. Embryo quality was assigned by embryologists using Gardner Criteria. R statistical package was used, and the blastulation groups were compared using analysis of variance (ANOVA) for continuous variables and chi-squared tests for categorical variables. The Bonferroni correction was used to adjust for multiple comparisons. One hundred seventeen IVF cycles met our inclusion criteria. Of these, 20 (17.1%) had low, 74 (63.2%) had intermediate, and 23 (19.7%) had high blastulation rates. Low blastulation rate was associated with a lower number of blastocysts, including fewer high-quality blastocysts. The mean number of oocytes retrieved was highest (18.1) in the group with the lowest blastulation rate, and lowest (13.4) in those with the highest blastulation rate, although this did not reach statistical significance. There were no significant differences between blastulation rates and age, gravidity, prior live birth, anti-mullerian hormone, estradiol and progesterone levels on the day of ovulation trigger, follicle-stimulating hormone dose, or fertility diagnosis. Conclusions: High blastulation rate is associated with a greater number of blastocysts, including a greater number of high-quality blastocysts. Higher oocyte yield, however, is not associated with improved blastulation rates. Blastulation rates, blastocyst number, and quality remain difficult to predict based on cycle characteristics alone, and oocyte yield may not be an accurate predictor of either outcome. Precis High oocyte yield may be associated with a lower blastulation rate and a lower number of high-quality blastocysts.