Table 2.

Mean values of systolic and diastolic BP recorded in women in the third trimester of pregnancy with 95% confidence intervals (CI) grouped by categorical variables (in brackets p values for significance of difference between categories)

Variables	N	SBB	95% CI	DBP	95% CI
PM2.5 (in μg/m3)
<26.6	149	113.6	111.4–114.8	71.0	69.7–72.3
26.7–45.9	147	115.3	113.6–117.0	73.0	71.8–74.2
>45.9	114	116.5	114.5–118.5	72.0	70.6–73.5
		(F = 2.61, p = 0.075)		(F = 2.49, p = 0.085)
ETSa
No	311	114.7	113.5–115.8	72.3	71.4–73.1
Yes	99	116.1	113.9–118.3	71.1	69.5–72.8
		(t = −1.185, p = 0.237)		(t = 1.295, p = 0.196)
Older siblings
No	259	116.1	114.8–117.4	72.9	71.9–73.9
1 or more	151	113.2	111.6–114.3	70.5	69.3–71.7
		(t = 2.698, p = 0.007)		(t = 3.045, p = 0.003)
Excessive GWG
No	312	113.7	112.6–114.9	71.7	70.8–72.5
Yes	98	119.2	117.0–121.4	73.0	71.4–74.7
		(t = −4.538, p = 0.000)		(t = −1.463, p = 0.144)

Missing blood measurements for 20 persons

^aSelf-reported ETS exposure