Table 3 Association of PM2.5 and HDP by gestational periods
| Â | No. of cases | (%) | Crude RR (95% CI) | Adjusted RR (95% CI) | P for trend |
|---|---|---|---|---|---|
0–12 gestational weeks | |||||
 Continuous | 440 | 5.1 | 4.03 (2.11–7.72) | 3.89 (1.45–10.43) |  |
 Q1 (< 46.36) | 76 | 3.5 | Reference (1.00) | Reference (1.00) |  |
 Q2 (46.36–54.54) | 103 | 4.7 | 1.33 (0.99–1.79) | 1.30 (0.93–1.82) |  |
 Q3 (54.54–60.06) | 129 | 5.9 | 1.67 (1.26–2.22) | 1.66 (1.11–2.48) |  |
 Q4 (≥ 60.06) | 132 | 6.0 | 1.70 (1.28–2.26) | 1.67 (1.10–2.53) | < 0.01 |
13–20 gestational weeks | |||||
 Continuous | 440 | 5.0 | 1.11 (0.66–1.87) | 0.71 (0.40–1.27) |  |
 Q1 (< 44.41) | 113 | 5.1 | Reference (1.00) | Reference (1.00) |  |
 Q2 (44.41–52.03) | 105 | 4.8 | 0.93 (0.71–1.21) | 0.85 (0.65–1.12) |  |
 Q3 (52.03–56.35) | 109 | 5.0 | 0.98 (0.75–1.27) | 0.88 (0.67–1.15) |  |
 Q4 (≥ 56.35) | 113 | 5.2 | 1.02 (0.78–1.32) | 0.85 (0.64–1.12) | 0.82 |
0–20 gestational weeks | |||||
 Continuous | 440 | 5.0 | 2.22 (1.05–4.68) | 1.00 (0.38–2.61) |  |
 Q1 (< 47.35) | 97 | 4.4 | Reference (1.00) | Reference (1.00) |  |
 Q2 (47.35–51.42) | 103 | 4.7 | 1.06 (0.80–1.40) | 0.90 (0.67–1.23) |  |
 Q3 (51.42–57.81) | 111 | 5.1 | 1.14 (0.87–1.50) | 0.89 (0.65–1.24) |  |
 Q4 (≥ 57.81) | 129 | 5.9 | 1.33 (1.03–1.74) | 1.01 (0.73–1.41) | 0.02 |