Table 1.

Criteria for defining RIF

Author	Number of ET *	Number of embryos **
Coulam, 1995	several	12
Tan et al., 2005	2-6	≥10
PGD Consortium	≥3	≥10
Margalioth et al., 2006	3	3
Rinehart, 2007	several	≥8 8-cell embryos ≥5 blastocysts
Coughlan et al., 2014 woman under the age of 40 years	≥3	4

^*Fresh or frozen ET procedures

^**High-grade embryos