Table 2.

Interaction between technique and difficult ET on CPR

	OR (95% CI)	p value
Direct easy ET	1
Afterload easy ET	0.97 (0.82–1.14)	0.685
Afterload difficult ET	0.85 (0.67–1.08)	0.197
Direct difficult ET	0.62 (0.49–0.77)	<0.001

Reference value: direct easy ET (OR = 1). CPR, clinical pregnancy rate; ET, embryo transfer. Results are reported as odds ratio (OR) and confidence interval (CI) and corrected by female and male age, year of procedure and blastocyst grading, and relative interactions. Standard errors of results were adjusted by clustering for the same couple