Table 2.
The potential confounders
| Feature | Took drug | Did not take drug | OR (95% CI) | P |
|---|---|---|---|---|
| Medical history | ||||
| History of asthma | 13.6% | 9.9% | 1.32 (1.15, 1.52) | 1.0 × 10−4 |
| History of indigestion | 75.7% | 66.2% | 1.19 (1.08, 1.32) | 0.001 |
| History of back pain | 52.6% | 42.7% | 1.11 (1.01, 1.22) | 0.028 |
| History of migraine | 53.7% | 36.5% | 1.46 (1.33, 1.60) | 5.4 × 10−16 |
| Pre‐pregnancy BMIa | M 23.3 | M 22.6 | 1.03 (1.02, 1.04) | 8.0 × 10−6 |
| In period 18‐32 wk | ||||
| In poor healthb | 32.8% | 18.8% | 1.18 (1.12, 1.25) | 8.0 × 10−9 |
| Had a cold | 48.5% | 34.3% | 1.44 (1.32, 1.59) | 7.7 × 10−15 |
| Had ‘flu | 8.7% | 3.8% | 1.37 (1.10, 1.70) | 0.005 |
| Had other infection | 7.1% | 3.4% | 1.33 (1.19, 1.49) | 8.2 × 10−7 |
| Had a headache | 80.6% | 46.4% | 3.89 (3.52, 4.29) | 5.5 × 10−160 |
| Lifestyle | ||||
| Healthy diet scorea | M ‐ 0.11 | M + 0.09 | 0.87 (0.83, 0.92) | 2.4 × 10−8 |
| Processed diet scorea | M + 0.07 | M ‐ 0.05 | 1.06 (1.01, 1.11) | 0.014 |
| Drank no alcohol | 45.0% | 53.7% | 0.66 (0.60, 0.72) | 1.1 × 10−19 |
| Social conditions | ||||
| Domestic chemical scorea | M 11.4 | M 10.5 | 1.02 (1.01, 1.03) | 0.002 |
| Parity 1+ | 62.6% | 49.4% | 1.18 (1.12, 1.24) | 6.2 × 10−11 |
Features of the mother that independently predicted whether she had taken paracetamol in the period 18‐32 weeks. Final model – N = 9522; pseudo‐R 2 = 14.35%. Details of variables are given in the Supplementary Material.
BMI, body mass index; CI, confidence interval; M, mean; OR, odds ratio or mean difference.
a
Odds ratio for a continuous scale.
b
Subjective measure reported by the mother at 32 wk.