Table 1.
Patients’ baseline characteristics
| Parameter | Day 3 ET | Day 5 ET |
|---|---|---|
| (n = 10,864) | (n = 1146) | |
| Age (years) | 31.3 ± 5.1 | 29.7 ± 4.5 |
| BMI (kg/m2) | 22.0 (3.0) | 22.0 (4.5) |
| bFSH (IU/L) | 7.16 (2.5) | 6.57 (2.0) |
| Duration of infertility (years) | 3 (4) | 3 (3) |
| Primary infertility (%) | 49.2 | 55.2 |
| Second infertility (%) | 50.8 | 44.8 |
| First treatment cycle (%) | 84.3 | 88.1 |
| Cause of infertility (%) | ||
| tubal pathology | 44.5 | 58.5 |
| male factors | 27.5 | 29.8 |
| advanced age (≥35 years) | 11.1 | 14.6 |
| PCOS | 6.2 | 11.5 |
| endometriosis | 3.5 | 3.3 |
| pelvic pathology | 6.5 | 6.5 |
| others | 3.8 | 4.1 |
| unexplained factors | 13.3 | 11.2 |
| ART (%) | ||
| IVF | 69.8 | 72.2 |
| ICSI | 28.8 | 25.6 |
| IVF + ICSI | 1.4 | 2.2 |
| Stimulation protocol (%) | ||
| GnRH-a long protocol | 82.8 | 93.5 |
| GnRH-a prolonged (modified) protocol | 11.1 | 5.8 |
Note: ART: assisted reproductive technology; IVF + ICSI: IVF + rescue ICSI or IVF + late ICSI; GnRH-a: gonadotropin-releasing hormone agonist; PCOS: polycystic ovary syndrome