Table 1.
Baseline characteristics of single vitrified embryo transfer cycles.
| 0-3 m | 3-12 m | >12 m | p value | |||
|---|---|---|---|---|---|---|
| p | p1 | p2 | ||||
| number of cycles, n | 4892 | 3499 | 1415 | |||
| maternal age at OPU, median (IQR) | 31 (28~36) | 32 (28~36) | 30 (27~33) | <0.001 | 0.330 | <0.001 |
| maternal BMI, median (IQR) | 21.5 (19.7~23.5) | 21.5 (19.8~23.6) | 21.6 (19.8~23.7) | 0.237 | 0.360 | 0.300 |
| type of infertility, n (%) | 0.004 | 0.003 | 0.261 | |||
| primary | 2835 (58.0) | 1900 (54.3) | 794 (56.1) | |||
| secondary | 2057 (42.0) | 1599 (45.7) | 621 (43.9) | |||
| length of infertility, median (IQR) | 3 (2~4) | 3 (2~5) | 3 (2~5) | 0.002 | 0.611 | 0.002 |
| main infertility causes, n (%) | 0.091 | 0.236 | 0.139 | |||
| female factor | ||||||
| tubal | 2538 (51.9) | 1841 (52.6) | 833 (58.9) | |||
| ovulation | 1082 (22.1) | 769 (22.0) | 372 (26.3) | |||
| DOR | 1096 (22.4) | 658 (18.8) | 157 (11.1) | |||
| EMT | 465 (9.5) | 364 (10.4) | 126 (8.9) | |||
| others | 958 (19.6) | 743 (21.2) | 199 (14.1) | |||
| male factor | 466 (9.5) | 356 (10.2) | 149 (10.5) | |||
| male and female factors | 547 (11.2) | 347 (9.9) | 142 (10.0) | |||
| unexplained | 184 (3.8) | 117 (3.3) | 35 (2.5) | |||
| number of oocytes retrieved, median (IQR) | 12.0 (6.3~18.0) | 11.0 (7.0~16.0) | 14.0 (10.0~19.0) | <0.001 | 0.040 | <0.001 |
| development stage of embryo transferred, n (%) | <0.001 | 0.065 | <0.001 | |||
| cleavage embryo | 1031 (21.1) | 679 (19.4) | 183 (12.9) | |||
| blastocyst | 3861 (78.9) | 2820 (80.6) | 1232 (87.1) | |||
| number of previous thawing, n (%) | <0.001 | <0.001 | <0.001 | |||
| 0 | 4655 (95.2) | 2396 (68.5) | 949 (67.1) | |||
| ≥1 | 237 (4.8) | 1103 (31.5) | 466 (32.9) | |||
| endometrial preparation method, n (%) | <0.001 | <0.001 | <0.001 | |||
| artificial | 4281 (87.5) | 2746 (78.5) | 1166 (82.4) | |||
| natural | 214 (4.4) | 231 (6.6) | 100 (7.1) | |||
| others | 397 (8.1) | 522 (14.9) | 149 (10.5) | |||
| thickness of endometrium, median (IQR) | 9.2 (8.5~10.0) | 9.0 (8.3~10.0) | 9.0 (8.3~10.0) | <0.001 | <0.001 | <0.001 |
OPU, ovum pick-up; BMI, body mass index; DOR, diminished ovarian reserve; EMT, endometriosis; IQR, interquartile range.
p: group (0-3 m) vs. group (3-12 m) vs. group (>12 m), p1: group (0-3 m) vs. group (3-12 m), p2: group (0-3 m) vs. group (>12 m).
p1 and p2 were the corresponding p values adjusted by the method “False Discovery Rate (fdr)”.