Maternal PM2.5 exposure triggers preterm birth: a cross-sectional study in Wuhan, China

Table 4 Adjusted odd ratios of preterm births for each 10 μg/m³ increment in PM_2.5 exposure during the entire pregnancy and trimesters in each subtype

Subgroup	N	Entire pregnancy		First trimester		Second trimester		Third trimester
Subgroup	N	OR (95% CI)^a	p value	OR (95% CI)^a	p value	OR (95% CI)^a	p value	OR (95% CI)^a	p value
Maternal education, years
≤ 9	278	1.327 (1.115, 1.542)	0.002	1.154 (0.954, 1.359)	0.132	1.125 (1.039, 1.211)	0.004	1.060 (0.945, 1.172)	0.292
10–13	355	1.148 (0.905, 1.397)	0.235	0.991 (0.792, 1.193)	0.927	1.034 (0.946, 1.123)	0.447	1.097 (0.986, 1.210)	0.088
≥ 14	1468	1.282 (1.139, 1.427)	< 0.001	1.247 (1.123, 1.374)	< 0.001	1.035 (0.979, 1.092)	< 0.001	1.036 (0.970, 1.103)	0.287
Infant sex
Female	997	1.250 (1.104, 1.398)	< 0.001	1.110 (0.981, 1.240)	0.095	1.054 (1.000, 1.110)	0.058	1.076 (1.006, 1.147)	0.033
Male	1104	1.257 (1.107, 1.409)	< 0.001	1.233 (1.100, 1.370)	< 0.001	1.050 (0.990, 1.110)	0.106	1.033 (0.962, 1.105)	0.360
Season of conception
Warm	1412	0.998 (0.873, 1.126)	0.978	0.968 (0.853, 1.083)	0.584	1.026 (0.980, 1.072)	0.258	1.086 (1.031, 1.140)	0.002
Cold	689	1.882 (1.656, 2.114)	< 0.001	1.637 (1.442, 1.835)	< 0.001	1.175 (1.083, 1.267)	< 0.001	0.838 (0.697, 0.981)	0.027

Abbreviation: OR odds ratio, CI confidence interval
^a Adjusted for maternal age, years of education, delivery mode, gravidity, parity, season of conception, gestational diabetes, gestational hypertension, and sex of infant, without each categorized variable

ISSN: 2397-0642