Table 4.

Comparison of the clinical outcomes from single high-quality embryo transfers and double embryo transfers.

	Single high-quality embryo	Two embryos	P value
≤35 years (average age 29.92 years)
Embryo transfer cycles	956	5963
Pregnancy rate per cycle	487/956 (50.9%)	4003 (67.1%)	<.001
Implantation rate per cycle	439/956 (45.9%)	3554/5963 (59.6%)	<.001
Preterm birth (<37 wks)	51/439 (11.6%)	456/3554 (12.8%)	.543
36–37 years (average age 36.44 years)
Embryo transfer cycles	94	475
Pregnancy rate per cycle	41/94 (43.6%)	254 (53.5%)	.09
Implantation rate per cycle	36/94 (38.3%)	229/475 (48.2%)	.09
Preterm birth (<37 wks)	5/36 (13.9%)	31/229 (13.5%)	1
≥38 years (average age 40.36 years)
Embryo transfer cycles	130	571
Pregnancy rate per cycle	20/130 (15.4%)	222 (38.9%)	<.001
Implantation rate per cycle	17/130 (13.1%)	190/571 (33.3%)	<.001
Preterm birth (<37 wks)	2/17 (11.8%)	29/190 (15.3%)	1