Table II.
Pregnancy outcomes after single fresh or vitrified-warmed blastocyst transfer in natural cycle and CC cycles.
| Total | Natural cycle SBT | CC cycle | |||
|---|---|---|---|---|---|
| SBT | SVBT | ||||
| A | B | ||||
| No. of total embryos transferred | 1653 | 157 | 24 | 1143 | 329 |
| Average no. of embryos transferred per patient | 1 | 1 | 1 | 1 | 1 |
| Blastocyst grade | |||||
| A | 1040 (62.9) | 157 (100)a | 24 (100)a | 667 (58.4)b | 192 (58.4)b |
| B | 186 (11.3) | 0 (0)a | 0 (0)a,b | 154 (13.5)b | 32 (9.7)b |
| C | 347 (21.0) | 0 (0)a | 0 (0)a | 272 (23.8)b | 75 (22.8)b |
| D | 80 (4.8) | 0 (0)a | 0 (0)a,b | 50 (4.4)b | 30 (9.1)b |
| Endometrial thickness (mm) (range, median) | 9.2 ± 0.0 (6–20, 9) | 9.6 ± 0.2a (6–20, 9) | 10.3 ± 0.4a (7–16, 9) | 9.2 ± 0.1b (6–20, 9) | 9.1 ± 0.1b (6–16, 8) |
| Clinical pregnancy | 996 (60.3) | 109 (69.4)a | 11 (45.8)b | 692 (60.5)b | 184 (55.9)b |
| Ongoing pregnancy | 920 (55.7) | 102 (65.0)a | 10 (41.7)b | 639 (55.9)b | 169 (51.4)b |
| Live birth | 823 (49.8) | 88 (56.1)a | 7 (29.2)b | 572 (50.0)a | 156 (47.4)a,b |
| Miscarriage | 173 (17.4) | 21 (19.3) | 4 (33.3) | 120 (17.3) | 28 (15.2) |
Data are presented as n, n (%), or mean±SEM. Data with distinct superscripts (a, b) are significantly different from each other within each row (P < 0.05). Cochran–Armitage test for trends and chi-squared tests were used to evaluate group differences for blastocyst grade, clinical pregnancy, ongoing pregnancy, live birth and miscarriage. Endometrial thickness was analysed using Kruskal–Wallis test.