Table 3.
Maternal characteristics and birth outcomes according to different umbilical cord serum 3-epi-25(OH)D3 level at delivery
| Umbilical cord serum 3-epi-25(OH)D3 (nmol/L) | ||||||
|---|---|---|---|---|---|---|
| ≤ 1.00 | 1.01-1.50 | 1.51-2.00 | 2.01-3.00 | > 3.00 | P | |
| (n = 358) | (n = 267) | (n = 258) | (n = 282) | (n = 156) | ||
| Maternal characteristics | ||||||
| Maternal age, y | 29.8 ± 4.9 | 30.3 ± 4.7 | 30.8 ± 4.9 | 31.7 ± 4.7 | 32.3 ± 4.5 | <0.001 |
| Primigravida | 242 (67.6) | 175 (65.5) | 155 (60.1) | 146 (51.8) | 72 (46.2) | <0.001 |
| Prepregnancy BMI, kg/m2 | 20.6 ± 2.9 | 20.7 ± 2.9 | 20.5 ± 2.7 | 20.5 ± 2.5 | 20.8 ± 2.8 | 0.77 |
| Maternal prepregnant weight, kg | 51.9 ± 7.6 | 52.2 ± 7.8 | 51.6 ± 7.6 | 51.5 ± 6.8 | 51.8 ± 7.7 | 0.85 |
| Maternal weight at delivery, kg | 68.0 ± 9.2 | 68.1 ± 8.7 | 66.7 ± 8.8 | 66.5 ± 8.0 | 66.1 ± 8.7 | 0.02 |
| Maternal gestational weight gain, kg | 16.1 ± 4.6 | 16.0 ± 4.6 | 14.8 ± 4.2 | 15.0 ± 4.4 | 14.3 ± 4.1 | <0.001 |
| BMI at delivery, kg/m2 | 27.1 ± 3.5 | 27.2 ± 3.0 | 26.6 ± 3.1 | 26.5 ± 3.1 | 26.4 ± 2.8 | 0.02 |
| Smoker | 11 (3.1) | 5 (1.9) | 3 (1.2) | 7 (2.5) | 2 (1.3) | 0.48 |
| Alcohol drinker | 0 | 1 (0.4) | 0 | 0 | 1 (0.6) | 0.32 |
| Maternal glycemic status, AUCglu | 768 ± 126 | 770 ± 133 | 778 ± 132 | 795 ± 140 | 815 ± 122 | 0.001 |
| Ambient solar radiation at delivery, MJ/m2 | 357.1 ± 67.0 | 375.0 ± 67.4 | 387.2 ± 77.7 | 402.7 ± 77.0 | 413.6 ± 80.3 | <0.001 |
| Maternal 25(OH)D3 level, nmol/L | 45.6 ± 16.1 | 49.8 ± 15.8 | 56.7 ± 15.5 | 63.1 ± 18.0 | 73.1 ± 22.2 | <0.001 |
| Birth outcomes | ||||||
| Gestation age at delivery, wk | 39.5 ± 1.4 | 39.5 ± 1.4 | 39.4 ± 1.3 | 39.3 ± 1.4 | 39.1 ± 1.5 | 0.01 |
| Preterm (≤37 wk) | 16 (4.5) | 8 (3.0) | 9 (3.5) | 14 (5.0) | 10 (6.4) | 0.48 |
| Cesarean delivery | 86(24.0) | 58(21.7) | 60(23.3) | 64(22.7) | 39(25.0) | 0.94 |
| Baby’s sex (male) | 185 (51.7) | 138 (51.7) | 140 (54.3) | 147 (52.1) | 82 (52.6) | 0.97 |
| LGA | 21 (6.1) | 17 (6.6) | 17 (6.8) | 17 (6.3) | 11 (7.5) | 0.99 |
| SGA | 38 (11.1) | 15 (5.8) | 26 (10.4) | 20 (7.5) | 14 (9.6) | 0.16 |
| Umbilical cord serum 25(OH)D3 level (nmol/L) | 33.4 ± 17.1 | 39.3 ± 14.4 | 42.3 ± 13.1 | 49.2 ± 16.9 | 58.0 ± 19.4 | <0.001 |
Continuous and categorical variables were expressed as mean ± SD and n (proportion in %), and were compared by ANOVA and χ 2 tests, respectively.
Abbreviations: 3-epi-25(OH)D3, isomeric form of 25(OH)D3; AUCglu, area under the curve of maternal glucose levels at the oral glucose tolerance test during pregnancy; BMI, body mass index; LGA, large for gestational age; SGA, small for gestational age.