Table 4.
Sensitivity analyses of the association between exposure to particulate matter (PM)a during the first trimester and fetal heart rate monitoring abnormalities
| n | No. of outcome | ORb per interquartile range increasec | 95% CId | ||
|---|---|---|---|---|---|
| Model 2 in Table 3 | 23,623 | 2,323 | 1.20 | 1.05 | 1.37 |
| Adjusted for exposure to Ozone, NO2, and SO2 during the first trimester | 19,215 | 1,623 | 1.23 | 1.05 | 1.44 |
| Excluding Okinawa area | 20,263 | 1,997 | 1.26 | 1.06 | 1.49 |
| Restricted to nulliparous | 10,503 | 1,483 | 1.25 | 1.03 | 1.52 |
| Restricted to non-smokers during pregnancy | 15,212 | 1,507 | 1.29 | 1.08 | 1.54 |
| Restricted to non-alcohol drinkers during pregnancy | 15,665 | 1,549 | 1.21 | 1.02 | 1.44 |
| Excluding women who delivered preterm (32–36 weeks of gestation) | 20,276 | 1,874 | 1.22 | 1.03 | 1.45 |
| Excluding women who delivered a baby small for gestational age | 21,419 | 1,952 | 1.28 | 1.08 | 1.51 |
| Excluding women with premature rupture of membranes | 21,352 | 2,037 | 1.24 | 1.05 | 1.47 |
| Excluding women who delivered a baby with congenital anomalies | 22,838 | 2,216 | 1.26 | 1.08 | 1.48 |
| Excluding women with scheduled cesarean deliveries | 18,575 | 2,274 | 1.23 | 1.05 | 1.44 |
aAs an indicator of PM, we used suspended PM, defined as airborne particles with a 100% cut-off level of 10-μm aerodynamic diameter under the Japan Air Quality Standards.
bOR = odds ratio.
cAdjusted for maternal age at delivery, birth year, season of conception, parity, smoking during pregnancy, alcohol drinking during pregnancy, gestational age at birth, premature rupture of membranes, mode of delivery, presence of congenital anomalies, small for gestational age, and exposure to PM during the second and third trimesters.
dCI = confidence interval.