| Characteristic | Vitamin D status, mean (± SD)* | ||
|---|---|---|---|
| Insufficient or deficient n = 95 | Sufficient n = 78 | p value† | |
| 25-Hydroxy-vitamin D, nmol/L | 54.5 ± 14.0 | 95.5 ± 17.8 | < 0.001 |
| Age, yr | 34.6 ± 4.0 | 34.4 ± 3.9 | 0.8 |
| Ethnic background, no. (%) | 0.3 | ||
| White | 56 (58.9) | 58 (74.4) | |
| Black | 3 (3.2) | 1 (1.3) | |
| Other | 36 (37.9) | 19 (24.4) | |
| Body mass index | 24.8 ± 4.7 | 23.3 ± 3.8 | 0.02 |
| Gravidity | 0.8 ± 1.1 | 0.9 ± 1.3 | 0.6 |
| Parity | 0.2 ± 0.5 | 0.3 ± 0.6 | 0.5 |
| Duration of infertility, mo | 20.7 ± 15.1 | 17.5 ± 12.3 | 0.1 |
| Follicle-stimulating hormone, baseline, IU/L | 6.4 ± 1.9 | 6.8 ± 2.3 | 0.9 |
| Antral follicle count, baseline, no. of follicles | 15.9 ± 8.4 | 17.7 ± 10.3 | 0.2 |
| Previous IVF cycles, no. | 0.7 ± 1.0 | 0.6 ± 1.0 | 0.4 |
| Season in which IVF cycle was performed, no. (%) of patients | 0.8 | ||
| Spring | 50 (52.6) | 41 (52.6) | |
| Summer | 31 (32.6) | 28 (35.9) | |
| Fall | 14 (14.7) | 9 (11.5) | |
Note: IVF = in vitro fertilization, SD = standard deviation. *Unless otherwise stated. †χ2 (categorical) and Student t or Mann–Whitney U (continuous) test; statistically significant, p < 0.05.