Table 2.
Cycle characteristics during the embryo transfer.
| Characteristic | NC (n = 4306) | HRT (n = 1007) | GnRH-a+HRT (n = 846) | P | |
|---|---|---|---|---|---|
| Serum progesterone levels on the day before transplantation (ng/ ml) | 9 (6.4, 13.1) | 9.3 (7, 12.4) | 9 (6.7, 11.9) | 0.257 | |
| Embryo stage at transfer, n (%) | 0.007 | ||||
| Cleavage (%) | 996/4306 (23.1%) | 191/1007 (19.0%)* | 190/846 (22.5%) |
||
| Blastocyst (%) | 3237/4306 (75.2%) | 797/1007 (79.1%)* | 631/846 (74.6%) |
||
| Cleavage +Blastocyst (%) | 73/4306 (1.70%) |
19/1007 (1.89%) |
25/846 (2.96%)* |
||
| Number of embryos transferred | 0.154 | ||||
| 1 | 2561/4306 (59.5%) | 614/1007 (61.0%) | 479/846 (56.6%) |
||
| 2 | 1745/4306 (40.5%) | 393/1007 (39.0%) | 367/846 (43.4%) |
||
| Post-thaw embryo survival rate | 14452/14936 (96.8%) |
3279/3385 (96.9%) | 3098/3219 (96.2%) |
0.274 | |
| High quality embryo transfer (%) | 2249/4306 (52.2%) | 482/1007 (47.9%)* | 444/846 (52.5%) |
0.038 | |
| Endometrial thickness (mm) on the day of ET | 11.9 (10.7, 13.2) |
11.5 (10.6, 12.5)* |
11.3 (10.4, 12.4)* |
<0.001 | |
*Compared to the NC, P < 0.05; # = compared to the HRT cycle, P < 0.05; NC, natural cycle; HRT, hormone replacement therapy; GnRH-a, gonadotropin-releasing hormone agonist; PCOS, polycystic ovary syndrome; ET, embryo transfer.