Table 2.
Effect of Vitamin C/E Supplementation on Maternal Outcomes by Smoking Status
| Outcome | Smoker Placebo (n = 763) | Smoker Vitamins (n = 788) | Non-Smokers Placebo (n = 4213) | Non-Smoker Vitamins (n = 4205) | Smokers | Non-Smokers | B-D Test* |
|---|---|---|---|---|---|---|---|
| Relative Risk (95% CI) | Relative Risk (95% CI) | p- Value | |||||
| Preeclampsia | 52/763 (6.8%) | 62/788 (7.9%) | 280/4213 (6.6%) | 296/4205 (7.0%) | 1.15 (0.81,1.65) | 1.06 (0.90,1.24) | 0.66 |
| Primary Composite Outcome† | 58/763 (7.6%) | 62/788 (7.9%) | 227/4213 (5.4%) | 243/4205 (5.8%) | 1.04 (0.73,1.46) | 1.07 (0.90,1.28) | 0.86 |
| Pregnancy Associated Hypertension | 236/763 (30.9%) | 278/786 (35.4%) | 1086/4209 (25.8%) | 1179/4203 (28.1%) | 1.14 (0.99,1.32) | 1.09 (1.01,1.17) | 0.47 |
| Placental Abruption | 11/748 (1.5%) | 1/782 (0.1%) | 25/4190 (0.6%) | 23/4175 (0.6%) | 0.09 (0.00,0.87) ** | 0.92 (0.52,1.62) | 0.010 |
| PPROM | 24/744 (3.2%) | 20/774 (2.6%) | 105/4179 (2.5%) | 104/4160 (2.5%) | 0.80 (0.45,1.44) | 1.00 (0.76,1.30) | 0.51 |
| Severe Preeclampsia | 28/763 (3.7%) | 27/788 (3.4%) | 113/4213 (2.7%) | 119/4205 (2.8%) | 0.93 (0.56,1.57) | 1.06 (0.82,1.36) | 0.68 |
| Pre-eclampsia Early Onset± | 12/763 (1.6%) | 8/788 (1.0%) | 31/4213 (0.7%) | 30/4205 (0.7%) | 0.65 (0.27,1.57) | 0.97 (0.59,1.60) | 0.43 |
*
Breslow-Day Test for Homogeneity comparing smokers to non-smokers
†
Severe hypertension OR mild hypertension with elevated liver enzymes, elevated serum creatinine, thrombocytopenia, eclampsia, SGA (<3rd%), medically indicated preterm birth or perinatal death.
±
Onset <34 weeks
**
Exact estimate of 95% confidence interval