Table 2 Result summary: maternal smoking in pregnancy and the risk of stillbirth
From: Maternal smoking and the risk of still birth: systematic review and meta-analysis
Assessment criteria | Odds ratio | 95% CI |
|---|---|---|
i) Overall pooled Results from main meta-analysis (25 studies) | 1.47 | 1.37-1.57 |
ii) Subgroup analysis by daily amount of cigarettes consumption | ||
1-9 cig/day (6 studies) | 1.09 | 0.97-1.24 |
≥ 10 cig/day (7 studies) | 1.52 | 1.30-1.78 |
iii) Subgroup analysis by gestation period at which stillbirth occurred | ||
Stillbirth ≥ 20 weeks (11 studies) | 1.43 | 1.32-1.54 |
Stillbirth ≥ 24 week (4 studies) | 1.58 | 1.21-2.06 |
Stillbirth ≥ 28 weeks (7 studies) | 1.33 | 1.18-1.49 |
iv) Subgroup analysis by geographic location | ||
North America (9 studies) | 1.39 | 1.29-1.50 |
Europe (11 studies) | 1.55 | 1.36-1.78 |
Asia (1 study) | 1.23 | 0.92-1.64 |
South America (1 study) | 1.40 | 1.00-1.96 |
Australia (3 studies) | 1.29 | 1.07-1.55 |
v) Subgroup analysis by quality | ||
High score (14 studies) | 1.41 | 1.28-1.55 |
Low score (11 studies) | 1.49 | 1.33-1.67 |