Table 1.

Patient and embryo characteristics

	IM	PV	p valuea
Age	31.7	31.7	NS
Gravidity	1.29	1.29	NS
Parity	0.71	0.71	NS
Diagnosisb			NS
Tubal factor	23.6%	24.2%	NS
Endometriosis	34.7%	39.3%	NS
PCOS	26.6%	26.5%	NS
Unexplained	8.5%	10.4%	NS
Male factor	37.7%	27.0%	0.03
Other	2.5%	1.9%	NS
Stage at freezingb
2 PN	6.5%	6.6%	NS
Cleaved	77.4%	74.9%	NS
Blastocyst	15.1%	17.5%	NS
Mean embryo grade at ETc	2.47	2.2	NS
Mean cell number at ETc	5.53	5.61	NS
Stage at transfer
Cleaved	84.4%	82%	NS
Non-expanded blast	7.0%	6.6%	NS
Expanded blastocyst	8.5%	11.4%	NS

^aBy Student’s t-test, except as noted

^bBy Chi square

^cFor non-blastocyst embryos only