Maternal Smoking during Pregnancy and its Association with Low Birth Weight

Introduction: Maternal smoking has been an important risk factor for low birth weight (LBW), preterm birth as well as small for gestational age. In this study, we try to analyze the association of maternal smoking during the different stages of pregnancy with outcome of birth weight. Methods: This is a cross-sectional hospital-based study, which was undertaken comprising of 1240 singleton live born baby in a Tertiary Care Teaching Hospital, Nepal. The enrollment occurred between June 2012 and May 2016 (Four years) among mothers who smoked any time during the current pregnancy. Based on the amount of smoking, the mothers with cigarette smoking were divided into four groups which includes: preconception, the first trimester, second trimester and third trimester. The data analyses were performed using Logistic regression and 95% confidence interval along with p-value. A p-value < 0.05 was considered statistically significant. Results: Of a total of 1240 singleton births, 328 (26.5%) were LBW. Among them, 149 (12.1%) of the mothers reported smoking during pregnancy. When compared with the nonsmoking groups, all the maternal smoking groups had higher incidences of LBW infants, especially when the mothers smoked > 10 cigarettes / day and during any stage of conception. Conclusions: Smoking during pregnancy is associated with an increased incidence of LBW among the infants. In addition, the newborns of mothers who smoked >10 cigarettes / day were most susceptible to having LBW, irrespective of the stage of pregnancy during which the mothers smoked.