Table 1 Demographic characteristics of the patients
Number of frozen blastocysts | ||||
|---|---|---|---|---|
0 | 1–2 | ≥ 3 | P | |
Number of patients | 1561 | 2943 | 4172 | |
Average number of frozen blastocysts | 0 | 1.5 ± 0.5 | 4.9 ± 1.5 | |
Age (years) | 29.9 ± 3.9 | 29.9 ± 3.6 | 29.7 ± 3.5 | 0.077 |
Years of infertility | 3.0 (1.0, 18.0) | 3.0 (1.0, 19.0) | 3.0 (1.0, 19.0) | < 0.001 |
AMH (ng/mL) | 4.9 (0.2, 18.0) | 5.1 (0.1, 48.6) | 5.7 (0.7, 34.5) | < 0.001 |
FSH (mIU/mL) | 7.2 ± 1.8 | 7.2 ± 1.6 | 7.2 ± 1.8 | 0.359 |
AFC | 15.3 ± 6.0 | 15.5 ± 5.9 | 16.4 ± 5.9 | < 0.001 |
BMI | 22.0 ± 3.0 | 22.0 ± 3.0 | 21.9 ± 3.0 | 0.100 |
Primary infertility | 1038 (66.5%) | 1948 (66.2%) | 2757 (66.1%) | 0.958 |
Estradiol (pg/mL) | 2669.0 (433.9, 6500.0) | 2705.0 (194.5, 6600.0) | 2830.0 (434.0, 6880.0) | < 0.001 |
Progesterone (ng/mL) | 0.8 ± 0.3 | 0.8 ± 0.3 | 0.8 ± 0.3 | 0.069 |
LH (mIU/mL) | 1.1 (0.1, 7.2) | 1.2 (0.1, 6.2) | 1.2 (0.1, 5.1) | 0.930 |
Endometrial thickness | 12.3 ± 2.6 | 12.0 ± 2.6 | 12.0 ± 2.6 | 0.066 |
Number of oocytes retrieved | 13.0 ± 3.5 | 13.5 ± 3.4 | 15.3 ± 3.8 | < 0.001 |
Type of treatment | < 0.001 | |||
IVF | 816 | 1790 | 2963 | |
ICSI | 745 | 1153 | 1209 | |
Number of 2PN | 5.7 ± 2.9 | 7.6 ± 2.8 | 10.2 ± 3.1 | < 0.001 |
Blastocyst formation rate (%)a | 30.8 | 44.8 | 70.1 | < 0.001 |
Number of embryo transfer | < 0.001 | |||
1 | 713 | 1456 | 2756 | |
2 | 848 | 1487 | 1416 | |
OHSS rate (%) | 1.8 | 1.9 | 2.1 | 0.751 |