Variables | n* | % | |
---|---|---|---|
Maternal age at delivery (years) | <25 | 3,205 | 3.9 |
25-29 | 13,420 | 16.2 | |
30-34 | 28,359 | 34.3 | |
≥35 | 37,789 | 45.6 | |
Parity | 0 | 49,978 | 60.4 |
≥1 | 32,778 | 39.6 | |
Smoking during pregnancy | No | 65,218 | 96.4 |
Yes | 2,416 | 3.6 | |
Alcohol drinking during pregnancy | No | 57,553 | 96.0 |
Yes | 2,395 | 4.0 | |
Prepregnancy body mass index (kg/m2) | <18.5 | 13,772 | 19.6 |
18.5-24.9 | 51,449 | 73.2 | |
≥25.0 | 5,066 | 7.2 | |
Infertility treatment | No | 69,624 | 84.1 |
Ovarian stimulation/artificial insemination by sperm from husband |
5,276 | 6.4 | |
Assisted reproductive technology | 7,873 | 9.5 | |
Past history of gestational diabetes mellitus |
No | 82,712 | 99.9 |
Yes | 61 | 0.1 | |
Season of conception | Spring (March-May) | 19,969 | 24.1 |
Summer (June-August) | 20,285 | 24.5 | |
Autumn (September-November) | 21,443 | 25.9 | |
Winter (December-February) | 21,076 | 25.5 |
Exposure over the first trimester (0-13 weeks of gestation) |
Exposure over the 3 months before pregnancy |
Exposure over the second trimester (14-27 weeks of gestation) |
|||||
---|---|---|---|---|---|---|---|
No. of women |
Mean (SD) | Percentile | Mean (SD) | Mean (SD) | |||
25 | 50 | 75 | |||||
Total PM2.5 (μg/m3) | 82,773 | 16.8 (2.6) | 14.9 | 16.1 | 18.5 | 16.7 (2.8) | 16.8 (2.6) |
PM2.5 components (μg/m3)* | |||||||
Total carbon | 67,136 | 4.0 (0.5) | 3.7 | 4.1 | 4.3 | 3.9 (0.6) | 3.9 (0.6) |
OC | 67,136 | 2.7 (0.4) | 2.4 | 2.7 | 2.9 | 2.6 (0.5) | 2.6 (0.4) |
EC | 67,136 | 1.3 (0.2) | 1.2 | 1.3 | 1.4 | 1.3 (0.2) | 1.3 (0.2) |
Nitrate | 67,136 | 1.4 (0.8) | 0.6 | 1.3 | 2.1 | 1.2 (0.8) | 1.3 (0.8) |
Sulfate | 67,136 | 2.8 (1.0) | 1.9 | 2.8 | 3.6 | 2.8 (1.1) | 2.9 (1.0) |
Ammonium | 67,136 | 1.5 (0.3) | 1.2 | 1.5 | 1.8 | 1.4 (0.3) | 1.5 (0.3) |
Chloride | 67,136 | 0.20 (0.13) | 0.08 | 0.15 | 0.34 | 0.19 (0.15) | 0.19 (0.13) |
Sodium | 67,136 | 0.15 (0.03) | 0.12 | 0.15 | 0.17 | 0.15 (0.03) | 0.15 (0.03) |
Potassium | 67,136 | 0.07 (0.01) | 0.06 | 0.07 | 0.08 | 0.07 (0.02) | 0.07 (0.01) |
Calcium | 67,136 | 0.07 (0.02) | 0.06 | 0.07 | 0.09 | 0.07 (0.02) | 0.07 (0.02) |
Ozone (ppb) | 82,773 | 35.9 (7.4) | 29.3 | 35.0 | 42.7 | 35.7 (7.5) | 36.7 (7.6) |
Ambient temperature (°C) | 82,773 | 16.5 (7.0) | 9.7 | 16.7 | 23.3 | 16.9 (7.2) | 16.7 (6.9) |
No. of women | No. of outcomes |
OR per IQR increase (95% CI)* |
|
---|---|---|---|
Exposure over the first trimester (0-13 weeks of gestation) | |||
Single-exposure period | 82,773 | 3,953 | 1.09 (1.03-1.16) |
Multiexposure period** | 82,773 | 3,953 | 1.09 (1.02-1.16) |
Sensitivity analyses | |||
Restricted to nonsmokers during pregnancy | 65,218 | 3,185 | 1.10 (1.02-1.18) |
Restricted to nonalcohol drinkers during pregnancy | 57,553 | 3,145 | 1.11 (1.04-1.19) |
Restricted to women with prepregnancy body mass index <25.0 kg/m2 | 65,221 | 2,710 | 1.09 (1.01-1.17) |
Restricted to women with spontaneous pregnancy | 69,624 | 3,149 | 1.08 (1.01-1.16) |
Additionally adjusted for ozone concentration and ambient temperature over the first trimester |
82,773 | 3,953 | 1.11 (1.02-1.22) |
Restricted to women who delivered in hospitals within 10 km from the monitoring sites |
61,436 | 2,969 | 1.08 (1.01-1.14) |
Exposure over the 3 months before pregnancy | |||
Single-exposure period | 82,773 | 3,953 | 1.00 (0.94-1.05) |
Multiexposure period** | 82,773 | 3,953 | 0.98 (0.93-1.04) |
Exposure over the second trimester (14-27 weeks of gestation) | |||
Single-exposure period | 82,773 | 3,953 | 1.06 (1.00-1.12) |
Multiexposure period** | 82,773 | 3,953 | 1.04 (0.98-1.11) |
Model | OR per IQR increase (95% CI)* | |
---|---|---|
Total carbon | Single-exposure period | 1.09 (1.04-1.14) |
Multiexposure period** | 1.07 (0.98-1.16) | |
Additionally adjusted for total PM2.5 | 1.06 (0.97-1.16) | |
OC | Single-exposure period | 1.10 (1.04-1.16) |
Multiexposure period** | 1.10 (1.00-1.21) | |
Additionally adjusted for total PM2.5 | 1.10 (1.00-1.21) | |
EC | Single-exposure period | 1.06 (1.00-1.12) |
Multiexposure period** | 1.04 (0.96-1.12) | |
Additionally adjusted for total PM2.5 | 1.03 (0.94-1.12) | |
Nitrate | Single-exposure period | 1.16 (1.05-1.28) |
Multiexposure period** | 1.06 (0.92-1.23) | |
Additionally adjusted for total PM2.5 | 1.03 (0.88-1.21) | |
Sulfate | Single-exposure period | 1.01 (0.91-1.12) |
Multiexposure period** | 0.97 (0.87-1.09) | |
Additionally adjusted for total PM2.5 | 0.93 (0.78-1.10) | |
Ammonium | Single-exposure period | 1.15 (1.04-1.28) |
Multiexposure period** | 1.02 (0.87-1.19) | |
Additionally adjusted for total PM2.5 | 1.10 (0.88-1.38) | |
Chloride | Single-exposure period | 1.20 (1.07-1.34) |
Multiexposure period** | 1.12 (0.98-1.28) | |
Additionally adjusted for total PM2.5 | 1.19 (0.99-1.43) | |
Sodium | Single-exposure period | 0.99 (0.89-1.10) |
Multiexposure period** | 0.97 (0.84-1.13) | |
Additionally adjusted for total PM2.5 | 0.98 (0.83-1.15) | |
Potassium | Single-exposure period | 1.05 (0.99-1.10) |
Multiexposure period** | 1.03 (0.96-1.09) | |
Additionally adjusted for total PM2.5 | 1.02 (0.96-1.09) | |
Calcium | Single-exposure period | 1.03 (0.96-1.10) |
Multiexposure period** | 1.01 (0.93-1.10) | |
Additionally adjusted for total PM2.5 | 0.99 (0.90-1.09) |