Table 2. Cycle characteristics and pregnancy outcomes stratified by the percent change of endometrial thickness.
| Characteristics | >5% decrease (n=405) | ±5% plateau (n=1,259) | >5% increase (n=1,104) | P value |
|---|---|---|---|---|
| Cycle characteristics | ||||
| Duration of follicular growth (days) | 13.2±2.1 | 13.4±3.8 | 13.3±2.2 | 0.498 |
| No. of >14 mm follicles on trigger day | 1.0±0.2 | 1.0±0.1 | 1.0±0.1 | 0.362 |
| Peak estradiol level (pg/mL) | 260.1±96.3 | 256.8±87.6 | 254.7±87.3 | 0.569 |
| EMT on trigger day (mm) | 11.25±2.06 | 11.37±2.34 | 10.04±1.66 | <0.001 |
| EMT on FET day (mm) | 9.70±1.87 | 11.38±2.35 | 12.21±2.06 | <0.001 |
| Post-trigger EMT absolute difference (mm) | −1.55±0.91 | 0.01±0.17 | 2.17±1.15 | <0.001 |
| Post-trigger EMT percent difference (%) | −13.6±7.1 | 0.1±1.6 | 22.1±12.2 | <0.001 |
| Spontaneous LH surge, n (%) | 255 (63.0) | 791 (62.8) | 616 (55.8) | 0.001 |
| No. of embryos transferred, n (%) | 0.100 | |||
| Single | 51 (12.6) | 142 (11.3) | 157 (14.2) | |
| Double | 354 (87.4) | 1,117 (88.7) | 947 (85.8) | |
| Embryo stage at transfer, n (%) | 0.264 | |||
| Cleavage stage | 359 (88.6) | 1,146 (91.0) | 1,008 (91.3) | |
| Blastocyst stage | 46 (11.4) | 113 (9.0) | 96 (8.7) | |
| Transfer of ≥1 top-quality embryo, n (%) | 93 (23.0) | 338 (26.8) | 255 (23.1) | 0.071 |
| Pregnancy outcomes | ||||
| Positive hCG test, n (%) | 209 (51.6) | 701 (55.7) | 597 (54.1) | 0.341 |
| Clinical pregnancy, n (%) | 194 (47.9) | 652 (51.8) | 554 (50.2) | 0.374 |
| Intrauterine implantation, n/N (%) | 246/759 (32.4) | 848/2,376 (35.7) | 713/2,051 (33.9) | 0.197 |
| Early miscarriage, n/N (%) | 25/194 (12.9) | 98/652 (15.0) | 76/554 (13.7) | 0.688 |
| Ongoing pregnancy, n (%) | 165 (40.7) | 543 (43.1) | 474 (42.9) | 0.686 |
| Live birth, n (%) | 161 (39.8) | 528 (41.9) | 468 (42.4) | 0.649 |
Values are presented as mean ± standard deviation or number (percentage). EMT, endometrial thickness; FET, frozen-thawed embryo transfer; LH, luteinizing hormone; hCG, human chorionic gonadotrophin.