Table 4.

Exposure to NO₂ during different periods of pregnancy and SD scores of neonatal anthropometry: INMA study, 2003–2008 (Spain).

Neonatal score (weeks)	n	NO2 (per 10-μg/m3 increase)			NO2 > 34.5 μg/m3 (66th percentile)
		% diffa (95% CI)	p-Valueb	I2 (%)c	% diffa (95% CI)	p-Valueb	I2 (%)c
HC
NO2 0–12	2,284	–1.4 (–2.8, 0.0)	0.05	3.8	–1.4 (–5.6, 2.8)	0.50	0
NO2 12–20	2,235	–0.2 (–2.4, 2.0)	0.84	50.6	–0.8 (–7.9, 6.4)	0.83	55.6
NO2 20–34	2,138	0.3 (–2.6, 3.2)	0.82	65.8	–0.8 (–5.1, 3.4)	0.70	46.8
NO2 34–delivery	2,191	0.7 (–0.7, 2.0)	0.32	12.5	2.1 (–2.1, 6.3)	0.33	0
NO2 pregnancy	2,233	–0.4 (–3.4, 2.7)	0.81	57.6	–3.5 (–7.7, 0.9)	0.12	17.4
Length
NO2 0–12	2,286	–2.8 (–4.4, –1.2)	< 0.01	0	–3.4 (–7.9, 1.1)	0.14	0
NO2 12–20	2,286	–2.8 (–4.3, –1.2)	< 0.01	0	–5.1 (–12.3, 2.3)	0.18	52.9
NO2 20–34	2,284	–2.2 (–3.8, –0.5)	0.01	0	–1.1 (–5.7, 3.4)	0.63	0
NO2 34–delivery	2,283	–1.1 (–2.6, 0.4)	0.14	0	–1.7 (–6.3, 2.9)	0.48	0
NO2 pregnancy	2,284	–3.2 (–5.1, –1.3)	< 0.01	0	–6.2 (–10.4, –1.8)	0.01	0
Weight
NO2 0–12	2,317	–1.3 (–2.9, 0.3)	0.11	49.4	–1.3 (–5.8, 3.3)	0.58	0
NO2 12–20	2,317	–1.5 (–3.1, 0.1)	0.07	0	–2.8 (–7.3, 1.7)	0.23	34.1
NO2 20–34	2,261	–0.6 (–2.3, 1.1)	0.48	48.1	–0.3 (–7.7, 7.1)	0.94	51.8
NO2 34–delivery	2,259	0.4 (–1.1, 2.0)	0.56	29.9	0.5 (–7.0, 8.0)	0.90	50.5
NO2 pregnancy	2,260	–1.2 (–3.1, 0.8)	0.24	35.6	–3.3 (–7.6, 1.1)	0.15	9.2
aPercent of difference in SD scores of neonatal anthropometry and its 95% CI, obtained by combining cohort-specific estimates using meta-analysis. bp-Value according to likelihood ratio (LR) test. cI2 statistic of heterogeneity; estimates with I2 > 50% were derived using random effects models.