Table 2.
Frozen-thawed embryo transfer cycle characteristics and clinical outcomes.
| Cycle characteristics | Postinfection | Postvaccination | Immune group | Not-immune2021 group | Not-immune2019 group | P value |
|---|---|---|---|---|---|---|
| FET cycle characteristics | ||||||
| Number of ET | 44 | 220 | 264 | 125 | 283 | |
| Spontaneous natural cycle (%) | 38/44 (86.3) | 191/220 (86.8) | 229/264 (86.7) | 108/125 (86.4) | 245/283 (86.6) | .99 |
| Mean endometrial thickness, mm (mean ± SD) | 9.9 + 1.9 | 9.5 + 2 | 9.6 + 2 | 9.5 + 1.9 | 9.7 + 1.9 | .68 |
| Mean peak E2, pmol/L(mean ± SD) | 773 + 323 | 910 + 574 | 886 + 540 | 895 + 420 | 1112 + 645 | <.001 |
| Mean peak P, nmol/L (mean ± SD) | 2.9 + 1.7 | 2.79 + 1.6 | 2.81+1.6 | 2.87 + 1.7 | 2..94 + 1.9 | >.99 |
| Number of embryos transferred | 50 | 255 | 305 | 141 | 349 | |
| Median number of embryos transferred (IQR) | 1 (1–1) | 1 (1–1) | 1 (1–1) | 1 (1–1) | 1 (1–1) | |
| Cleavage-stage embryo transfer rate per transfer | 29/44 (65.9) | 119/220 (54.0) | 148/264 (56.1) | 67/125 (53.6) | 179/283 (63.2) | .13 |
| Clinical outcomes | ||||||
| Number of positive β-hCG | 16 | 58 | 74 | 36 | 75 | |
| Positive β-hCG per transfer (%) | 16/44 (36.4) | 58/220 (26.4) | 74/264 (28.0) | 36/125 (28.8) | 75/283 (26.5) | .71 |
| Positive β-hCG per patient (%) | 16/26 (61.5) | 58/115 (50.4) | 74/141 (52.5) | 36/93 (38.7) | 75/194 (38.7) | .017 |
| Number of sacs observed | 14 | 57 | 71 | 34 | 71 | |
| Implantation rate (%) | 14/50 (28.0) | 57/255 (22.3) | 71/305 (23.2) | 34/141 (24.1) | 71/349 (20.3) | .71 |
| Number of clinical pregnancies | 13 | 55 | 68 | 33 | 65 | |
| Clinical pregnancy rate per transfer (%) | 13/44 (29.5) | 55/220 (25.0) | 68/264 (25.6) | 33/141(26.4) | 65/283 (23.0) | .86 |
| Number of ongoing pregnancies | 12 | 54 | 66 | 32 | 65 | |
| Ongoing pregnancy rate per transfer (%) | 12/44 (27.3) | 54/220 (24.5) | 66/264 (25.0) | 32/141 (22.7) | 65/283 (23.0) | .95 |
Note: β-hCG = β-human chorionic gonadotropin; E2 = estradiol; ET = embryo transfer; FET = frozen-thawed embryo transfer; IQR = interquartile range; P = progesterone.