| Characteristic | Vitamin D status, no. (%) or mean ± SD | p value* | |
|---|---|---|---|
| Insufficient or deficient n = 95 | Sufficient n = 78 | ||
| IVF protocol, no. (%) | 0.08 | ||
| Long | 29 (30.5) | 34 (43.6) | |
| Antagonist | 64 (67.4) | 40 (51.3) | |
| Flare | 2 (2.1) | 4 (5.1) | |
| Day of hCG injection | 12.1 ± 1.3 | 11.9 ± 1.4 | 0.4 |
| Gonadotropin dose, IU | 2602.8 ± 1287.3 | 2547.1 ± 1330.3 | 0.8 |
| Follicle diameter > 14 mm, no. | 11.9 ± 6.5 | 11.7 ± 5.8 | 0.8 |
| Estradiol level on the day of hCG administration, pmol/L | 8556.7 ± 6187.3 | 9776.15 ± 5902.6 | 0.2 |
| Endometrial thickness on the day of hCG administration, cm | 1.0 ± 1.6 | 1.0 ± 0.2 | 0.5 |
| Oocytes retrieved, no. | 12.6 ± 7.4 | 12.7 ± 6.6 | 0.9 |
| Intracytoplasmic sperm injection, no. (%) | 74 (77.9) | 63 (80.8) | 0.4 |
| Embryos transferred, no. | 1.8 ± 1.0 | 1.8 ± 0.9 | 0.9 |
| Day of embryo transfer, no. (%) | |||
| Day 3 | 31 (32.6) | 19 (24.4) | 0.2 |
| Day 5 | 56 (58.9) | 56 (71.8) | 0.054.00 |
| Implantation rate, % | 25.6 | 34.5 | 0.6 |
| Clinical pregnancy rate, per cycle start, % | 34.7 | 52.5 | < 0.001 |
| Clinical pregnancy rate, per embryo transfer, % | 37.9 | 54.7 | < 0.001 |
Note: hCG = human chorionic gonadotropin, SD = standard deviation. *χ2 (categorical) and Students t or Mann–Whitney U (continuous) test; statistically significant, p < 0.05. †Follicle-stimulating hormone or human menopausal gonadotropin, depending on protocol.