Table 2 Relationship between VitD intake and obstetric outcomes among women who conceived without ART
Quintile for VitD | ||||||
|---|---|---|---|---|---|---|
Q1 (low) | Q2 | Q3 | Q4 | Q5 (high) | p-valuea | |
n = 17,687 | n = 17,407 | n = 17,254 | n = 17,532 | n = 17,415 | ||
VitD intake before pregnancy, μg/day, median (IQR) | 1.4 (0.8–1.8) | 3.0 (2.6–3.3) | 4.3 (4.0–4.7) | 6.0 (5.5–6.7) | 10.2 (8.7–12.8) | |
PTB at < 37 weeks | ||||||
Number, n | 729 | 784 | 724 | 704 | 749 | |
Occurrence, % | 4.1 | 4.5 | 4.2 | 4.0 | 4.3 | 0.812 |
aOR (95% CI) | 0.97 (0.89–1.09) | 1.08 (0.97–1.12) | 1 (Ref) | 0.95 (0.85–1.05) | 1.02 (0.92–1.13) | |
PTB at < 34 weeks | ||||||
Number, n | 145 | 157 | 138 | 119 | 145 | |
Occurrence, % | 0.8 | 0.9 | 0.8 | 0.7 | 0.8 | 0.361 |
aOR (95% CI) | 1.02 (0.81–1.30) | 1.14 (0.90–1.43) | 1 (Ref) | 0.85 (0.66–1.08) | 1.05 (0.83–1.33) | |
LBW < 2500 g | ||||||
Number, n | 1371 | 1397 | 1264 | 1256 | 1352 | |
Occurrence, % | 7.8 | 8.0 | 7.3 | 7.2 | 7.8 | 0.198 |
aOR (95% CI) | 1.00 (0.92–1.09) | 1.09 (1.01–1.18) | 1 (Ref) | 0.99 (0.91–1.07) | 1.09 (1.00–1.18) | |
LBW < 1500 g | ||||||
Number, n | 79 | 91 | 68 | 66 | 73 | |
Occurrence, % | 0.4 | 0.5 | 0.4 | 0.4 | 0.4 | 0.203 |
aOR (95% CI) | 1.17 (0.84–1.63) | 1.35 (0.98–1.87) | 1 (Ref) | 0.97 (0.69–1.37) | 1.12 (0.80–1.56) | |
SGA | ||||||
Number, n | 868 | 860 | 777 | 851 | 963 | |
Occurrence, % | 4.9 | 5.0 | 4.5 | 4.9 | 5.6 | 0.025 |
aOR (95% CI) | 1.06 (0.96–1.17) | 1.09 (0.99–1.21) | 1 (Ref) | 1.10 (0.99–1.22) | 1.26 (1.14–1.39) | |
HDP | ||||||
Number, n | 415 | 394 | 357 | 377 | 364 | |
Occurrence, % | 2.4 | 2.3 | 2.1 | 2.2 | 2.1 | 0.076 |
aOR (95% CI) | 1.05 (0.91–1.22) | 1.06 (0.92–1.23) | 1 (Ref) | 1.04 (0.90–1.21) | 1.00 (0.86–1.16) | |