Elective single blastocyst-stage transfers (n=240) Double blastocyst-stage embryo transfers (n=189) Adjusted odds ratio (95% CI)
Cumulative livebirth rate (%) 178 (74.2) 119 (63.0) 1.09 (0.68-1.75)
Subgroups
Age groups (years)
36-37 120/152 (78.9) 67/95 (70.5) 1.13 (0.56-2.28)
38-39 42/61 (68.9) 33/54 (61.1) 1.05 (0.48-2.30)
≥40 16/27 (59.3) 19/40 (47.5) 0.88 (0.29-2.65)
Quality of blastocysts
Good 123/159 (77.4) 40/48 (83.3) 0.47 (0.19-1.15)
Fair 55/81 (67.9) 79/141 (56.3) 1.56 (0.86-2.82)