| Maternal active smoking is an established risk factor for small for gestational age (SGA). The role of maternal passive smoking in SGA, however, is unclear. The present study analyzed data from a birth cohort study conducted in Lanzhou, China between 2010 and 2012 including 8,638 non-smoking women who delivered singleton live births. Among those, 775 were SGA and 7,863 were appropriate for gestational age (AGA). Multivariate logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Potential confounding variables included in the final models were maternal age, education, employment status during pregnancy, parity, maternal pre-pregnancy body mass index (BMI), gestational hypertension, prior delivery of a low birth weight (LBW) infant, and total energy intake during pregnancy. Exposure to passive smoking during pregnancy was associated with an increased risk of SGA (OR=1.29, 95% CI: 1.08, 1.54). Risk of SGA increased with increasing duration of exposure (Ptrend=0.003). Passive smoking exposure at home was associated with greater risk compared to exposure at other locations (OR=1.35, 95% CI: 1.11, 1.64 and OR=1.13, 95% CI: 0.78, 1.65, respectively). The results suggested a positive association between maternal passive smoking and risk of SGA. |
