Table 4. Incidence Risk Ratio for ≥ triple pregnancy stratified by quartile of mean number of embryos transferred1
Quartile (mean number of transferred embryos) IRR year (95% CI) p
1- (2.47-2-70) 0.87 (0.80-0.969 0.003
2- (2.71-2.97) 0.41 (0.19-0.86) 0.019
3- (2.98-3.13) 0.98 (0.93-1.04) 0.638
4- (3.14-3.42) 0.97 (0.92-1.04) 0.477

1Adjusted for age category