Table 4.

Clinical outcomes following transfer of vitrified cleavage embryos in different storage duration groups.

Storage Groups	I	II	III	IV	P-value
Storage duration (months)	1-6	7-12	13-36	37-84
No. of cycles	289	108	80	54
Mean storage duration (months)	3.63 ± 1.50	9.06 ± 1.75	23.36 ± 7.62	52.22 ± 11.86
Age at FET (years)	31.93 ± 3.75	32.42 ± 3.43	33.15 ± 3.65	33.69 ± 3.00	0.002
Endometrial thickness (mm)	9.92 ± 1.81	9.43 ± 1.83	9.96 ± 1.88	9.98 ± 1.86	0.081
Number of embryos transferred	2.31 ± 0.62	2.33 ± 0.60	2.25 ± 0.56	1.91 ± 0.62	P<0.001
Number of good-quality embryos transferred	1.73 ± 0.65	1.79 ± 0.64	1.73 ± 0.66	1.48 ± 0.54	0.032
Biochemical pregnancy rate	14 (4.8%)	3 (2.8%)	1 (1.3%)	3 (5.6%)	0.412
Implantation rate	155/667 (23.2%)	63/252 (25.0%)	43/180 (23.9%)	32/103 (31.1%)	0.384
Clinical pregnancy rate	118 (40.8%)	51 (47.2%)	34 (42.5%)	22 (40.7%)	0.710
Ongoing pregnancy rate	93 (32.2%)	44 (40.7%)	27 (33.8%)	19 (35.2%)	0.461
Live birth rate	91 (31.5%)	42 (38.9%)	26 (32.5%)	18 (33.3%)	0.579
Miscarriage rate	20 (16.9%)	6 (11.8%)	8 (23.5%)	2 (9.1%)	0.395
Multiple pregnancy rate	37 (31.4%)	12 (23.5%)	9 (26.5%)	9 (40.9%)	0.462
Ectopic pregnancy rate	7 (5.9%)	2 (3.9%)	0 (0.0%)	1 (4.5)	0.600

Data are mean ± SD, n (%) or n/N (%).