Table 5.
Stratification of risk of fetal growth restriction among offspring of 2635 pregnant women according to caffeine intake during pregnancy and caffeine half life (proxy for clearance)
| Caffeine intake (mg/day) | Risk of fetal growth restriction* | |
|---|---|---|
| Odds ratio (95% CI) | Test for trend | |
| Shorter caffeine half life (n=774)† | ||
| <100 | 1 | P=0.02 |
| 100-199 | 1.6 (0.9 to 3.0) | |
| 200-299 | 2.4 (1.3 to 4.4) | |
| ≥300 | 1.7 (0.9 to 3.3) | |
| Longer caffeine half life (n=764)† | ||
| <100 | 1 | P=0.8 |
| 100-199 | 1.1 (0.6 to 1.7) | |
| 200-299 | 0.6 (0.3 to1.3) | |
| ≥300 | 1.5 (0.7 to 2.9) | |
| Test for interaction of half life P=0.06 | ||
*Adjusted for maternal age, weight, height, ethnicity, parity, smoking status (salivary cotinine concentration), and alcohol intake and neonatal gestational age at delivery and sex.
†Shorter caffeine half life (≤median value)=faster clearance; longer half life (>median value)=slower clearance).