Table 2 Estimated regression coefficients (95% CIs) from the fitted models

Pre-treatment Dynamic
Separate Joint Separate Joint
Number of oocytes submodel
Intercept 2.09 (2.07 to 2.12) 2.10 (2.07 to 2.13) 2.09 (2.07 to 2.12) 2.09 (2.07 to 2.12)
Age (years) − 0.04 (− 0.05 to − 0.04) − 0.04 (− 0.05 to − 0.04) − 0.04 (− 0.05 to − 0.04) − 0.04 (− 0.05 to − 0.04)
Partner age (years) 0.01 (0.00 to 0.01) 0.01 (0.00 to 0.01) 0.01 (0.00 to 0.01) 0.00 (0.00 to 0.01)
Attempt number: 1st 0 0 0 0
2nd 0.06 (0.01 to 0.12) 0.06 (0.01 to 0.11) 0.06 (0.01 to 0.12) 0.08 (0.03 to 0.13)
3rd 0.17 (0.07 to 0.27) 0.14 (0.04 to 0.23) 0.17 (0.06 to 0.28) 0.15 (0.06 to 0.24)
4th or 5th 0.02 (− 0.24 to 0.29) 0.04 (− 0.20 to 0.27) 0.02 (− 0.24 to 0.26) 0.16 (− 0.07 to 0.38)
Fertilisation rate submodel
Intercept − 1.04 (− 1.06 to − 1.01) − 0.95 (− 0.98 to − 0.92) − 1.04 (− 1.07 to − 1.01) − 0.96 (− 0.99 to − 0.93)
Age (years) 0.01 (0.01 to 0.02) 0.02 (0.01 to 0.03) 0.01 (0.01 to 0.02) 0.02 (0.01 to 0.02)
Partner age (years) 0.00 (− 0.01 to 0.00) − 0.00 (− 0.01 to 0.00) 0.00 (− 0.01 to 0.00) 0.00 (− 0.01 to 0.00)
Embryo evenness submodel
Intercepts (log odds of ≤ k): k = 1 − 4.23 (− 4.37 to − 4.10) − 4.35 (− 4.50 to − 4.20) − 4.32 (− 4.47 to − 4.18) − 4.33 (− 4.48 to − 4.18)
K = 2 − 1.28 (− 1.37 to − 1.19) − 1.38 (− 1.48 to − 1.29) − 1.37 (− 1.47 to − 1.27) − 1.37 (− 1.47 to − 1.26)
K = 3 1.43 (1.34 to 1.51) 1.33 (1.24 to 1.42) 1.34 (1.25 to 1.44) 1.35 (1.25 to 1.46)
Age (years) 0.01 (− 0.01 to 0.02) 0.00 (− 0.01 to 0.02) 0.00 (− 0.01 to 0.02) 0.00 (− 0.03 to 0.03)
Partner age (years) 0.01 (0.00 to 0.02) 0.01 (0.00 to 0.02) 0.01 (0.00 to 0.02) 0.01 (0.00 to 0.02)
Sperm injected into egg − 0.21 (− 0.32 to − 0.10) − 0.27 (− 0.38 to − 0.16) − 0.28 (− 0.39 to − 0.16) − 0.26 (− 0.37 to − 0.14)
Number of oocytes 0.09 (0.01 to 0.17) 0.16 (− 0.17 to 0.53)
Fertilisation rate − 0.16 (− 0.23 to − 0.08) − 0.47 (− 0.71 to − 0.21)
Embryo fragmentation submodel
Intercepts (log odds of ≤ k): k = 1 − 4.91 (− 5.10 to − 4.74) − 5.11 (− 5.29 to − 4.92) − 5.06 (− 5.24 to − 4.88) − 5.06 (− 5.25 to − 4.88)
K = 2 − 2.27 (− 2.40 to − 2.13) − 2.44 (− 2.58 to − 2.31) − 2.41 (− 2.54 to − 2.27) − 2.40 (− 2.55 to − 2.25)
K = 3 − 0.15 (− 0.27 to − 0.03) − 0.33 (− 0.46 to − 0.20) − 0.29 (− 0.42 to − 0.17) − 0.28 (− 0.42 to − 0.14)
Age (years) − 0.02 (− 0.05 to − 0.00) − 0.03 (− 0.05 to − 0.01) − 0.03 (− 0.05 to 0.00) − 0.06 (− 0.1 to − 0.02)
Partner age (years) 0.01 (− 0.01 to 0.02) 0.01 (0.00 to 0.02) 0.01 (0.00 to 0.03) 0.01 (− 0.00 to 0.03)
Sperm injected into egg − 0.19 (− 0.35 to − 0.03) − 0.33 (− 0.48 to − 0.18) − 0.32 (− 0.48 to − 0.17) − 0.31 (− 0.48 to − 0.15)
Number of oocytes 0.22 (0.10 to 0.33) − 0.18 (− 0.67 to 0.29)
Fertilisation rate − 0.30 (− 0.41 to − 0.20) − 0.60 (− 0.93 to − 0.13)
Double embryo transfer submodel
Intercept 0.11 (0.06 to 0.17) 0.13 (0.07 to 0.19) 0.13 (0.06 to 0.19) 0.08 (0.02 to 0.14)
Age (years) 0.02 (0.01 to 0.04) 0.02 (0.01 to 0.04) 0.02 (0.00 to 0.03) − 0.01 (− 0.03 to 0.01)
Partner age (years) − 0.01 (− 0.02 to 0.00) − 0.01 (− 0.02 to 0.00) 0.00 (− 0.02 to 0.00) − 0.00 (− 0.01 to 0.01)
Attempt no: 1st 0 0 0 0
2nd 0.27 (0.15 to 0.39) 0.23 (0.11 to 0.35) 0.25 (0.13 to 0.37) 0.27 (0.15 to 0.38)
3rd 0.46 (0.23 to 0.70) 0.44 (0.19 to 0.67) 0.47 (0.23 to 0.72) 0.53 (0.31 to 0.75)
4th or 5th 0.72 (0.15 to 1.31) 0.60 (0.06 to 1.17) 0.63 (0.10 to 1.21) 0.69 (0.16 to 1.25)
Number of oocytes − 0.06 (− 0.13 to − 0.03) − 0.25 (− 0.50 to 0.01)
Fertilisation rate − 0.02 (− 0.09 to 0.05) − 0.34 (− 0.51 to − 0.10)
Embryo evenness − 0.14 (− 0.20 to − 0.08) − 0.09 (− 0.15 to − 0.02)
Embryo fragmentation − 0.12 (− 0.18 to − 0.06) − 0.05 (− 0.12 to 0.03)
Live birth event submodel
Intercept − 0.46 (− 0.51 to − 0.41) − 0.49 (− 0.54 to − 0.44) − 0.56 (− 0.64 to − 0.47) − 0.39 (− 0.73 to − 0.04)
Age (years) − 0.02 (− 0.04 to 0.00) − 0.02 (− 0.04 to − 0.01) − 0.01 (− 0.03 to 0.00) − 0.03 (− 0.05 to − 0.01)
Partner age (years) − 0.01 (− 0.02 to 0.00) − 0.01 (− 0.02 to 0.00) − 0.01 (− 0.02 to 0.00) 0.00 (− 0.01 to 0.00)
Number of oocytes 0.04 (− 0.03 to 0.12) − 0.13 (− 0.31 to 0.08)
Fertilisation rate 0.14 (0.07 to 0.21) − 0.16 (− 0.39 to 0.12)
Embryo evenness 0.07 (0.01 to 0.13) 0.03 (− 0.04 to 0.10)
Embryo fragmentation 0.04 (− 0.02 to 0.10) 0.04 (− 0.04 to 0.11)
DET 0.11 (0.01 to 0.22) − 0.13 (− 0.66 to 0.43)