Note: tPNa–timing to pronuclei appearance, tPNf–timing to pronuclei fading, t2–timing to two cells, t3–timing to three cells, t4–timing to four cells, t5–timing to five cells, t6–timing to six cells, t7–timing to seven cells, t8–timing to eight cells, tSB– timing to start blastulation, tB–timing to blastulation, s1–timing to complete t2-tPNf synchronous divisions, s2–timing to complete t4-t3 synchronous divisions, s3–timing to complete t8-t5 synchronous divisions, cc2–duration of the second cell cycle (t3-t2), cc3–duration of third cell cycle (t5-t3), KIDScore–known implantation diagnosis score. Values are the mean±- standard error, unless otherwise noted. Different superscript letters in a line represent significant differences (p<0.05). B– regression coefficient, CI–95% confidence interval. * Reference group.