[Association between maternal passive smoking during perinatal period and congenital heart disease in their offspring-based on a case-control study].

To explore the association between maternal passive smoking during perinatal period and congenital heart disease (CHD) in their offspring. A case-control study was designed. Data being used was based on a case-control study of congenital heart disease collected in Shaanxi province from January 2014 to December 2016. Cases under this study were perinatal infants diagnosed as CHD from 28 weeks of gestation to 7 days after birth, and fetus less than 28 weeks of gestation but diagnosed as CHD by ultrasonography. The controls would include newborn infants without any birth defects, born at the same period of the cases. Logistic regression model with confounding factors adjusted was established to analyze the association between maternal passive smoking status during perinatal period and CHD in their offspring. Subgroup analysis was carried out to explore its stability. A total of 2 259 subjects, consisting 695 cases and 1 564 controls were included in this study. Passive smokers accounted for 26.76 in the case group while only 6.01 in the control group. After adjusting for related confounding factors, the risk of CHD in the offspring of passive smokers was 3.32 times higher than that of the non-passive smokers (=3.32, 95: 2.41-4.56), during the perinatal period. Results also showed that related risk accumulated with the increase of exposure frequency to passive smoking. For mothers who smoked passively for 1-3 days per week, the risk of CHD in their offspring was 2.75 times higher than that of those non-passive smokers (=2.75, 95: 1.62-4.66). For mothers who smoked passively for more than 3 days per week, the risk was 3.62 times higher than the non-passive smokers (=3.62, 95: 2.48-5.29). Data from the subgroup analysis showed that the association between maternal passive smoking during perinatal period and CHD in their offspring appeared stable. Maternal passive smoking during perinatal period seemed a risk factor for congenital heart disease related to their offspring. Pregnant women should avoid exposure to second-hand smoke as much as possible, so as to prevent the harm from passive smoking.