Structural equation model of direct effects of prenatal exposure characteristics on infant’s birth outcomes.

BW-Birthweight; BL-Birth length; GA- Gestational age; NOx- Oxides of Nitrogen; GWG- gestational weight gain; BMIT1- pre-gestational body mass index in the first trimester; and Mage- maternal age. Latent variables: dietary factors (EFSF- energy foods and snacks; FFSF-spreads and fast foods; JFF- junk foods factor; PRFF-protein-rich foods; SFF- starch foods; NRFF-nuts and rice foods; VRFF-vegetable-rich foods; and ADF-alcoholic drinks); PhyEx- physical exercise; PSmoker- passive smoker; LSES -low socio-economic status, Linc- Low income; PLEduc- primary or less education; LSEH-Low socio-economic housing; Unemp- unemployed.