Table 6.
Comparison of demographic and clinical characteristics between subgroups of the day 5 ET group
| Parametera | Serum P levels (ng/ml), day 5 ET | P-value* | |
|---|---|---|---|
| <1.75 | ≥1.75 | ||
| No. of fresh cycles | 1066 | 80 | |
| Female age (years) | 29.5 ± 4.4 | 31.5 ± 5.2 | 0.002 |
| BMI (kg/m2) | 22.60 ± 3.31 | 21.95 ± 2.59 | 0.036 |
| Basal FSH (IU/L) | 6.61 ± 1.57 | 6.53 ± 1.83 | NS |
| Total dose of Gn (IU) | 1760.0 ± 635.5 | 2114.1 ± 680.7 | <0.001 |
| Serum E2 (pg/ml), hCG day | 7583.3 ± 2595.8 | 9200.6 ± 3038.1 | <0.001 |
| Serum LH (IU/L), hCG day | 1.6 ± 0.7 | 1.5 ± 0.7 | NS |
| Endometrial thickness (mm), hCG day | 12.2 ± 2.3 | 12.1 ± 2.5 | NS |
| No. of oocytes retrieved | 17.9 ± 5.0 | 19.7 ± 4.9 | 0.003 |
| No. of 2PN oocytes | 13.1 ± 3.8 | 14.4 ± 4.3 | 0.014 |
| No. of 2PN cleavage embryos | 12.9 ± 3.8 | 14.2 ± 4.3 | 0.003 |
| No. of available embryos | 9.7 ± 3.8 | 9.9 ± 4.8 | 0.031 |
| Fertilization rate (%) | 74.4 | 73.5 | NS |
| Cleavage rate (%) | 98.5 | 99.1 | NS |
| No. of transferred embryos | 1.08 ± 0.27 | 1.19 ± 0.39 | 0.017 |
| ET with top-quality blastocyst (%) | 58.7 | 52.7 | NS |
| Implantation rate (%) | 46.2 | 29.5 | 0.002 |
| CPR (%) | 41.4 | 21.3 | <0.001 |
Note: Day 5 ET subgroups according progesterone cut-off levels: <1.75 ng/ml, ≥1.75 ng/ml; NS = not statistically significant
aAll values are presented as the mean ± SD or count (%)
*Differences between subgroups were determined using Student’s t-test or the Mann–Whitney U test for continuous variables and the chi-square test or Fisher’s exact test for categorical variables