The Effects of Maternal Tobacco Use on Low Birth Weight in Texas 2001

Abstract

Low birth weight (LBW) is a major contributor to infant mortality and childhood morbidity and mortality. Maternal smoking is a major cause of low birth weight. This population-based retrospective cohort study examined the effects of maternal tobacco use during pregnancy on the incidence of LBW Computerized data of Texas 2001 live birth certificates were used, and only singleton births were analyzed. Descriptive statistics, relative risks, 95% confidence intervals, logistic regression analyses, and a multiple linear regression analysis were used to examine the association between maternal smoking and LBW. Mothers who smoked during pregnancy were twice as likely than non-smokers (95% Cl = 1.707 - 1.852) to have a low birth weight infant both before and after adjustment of covanates (sex of child; maternal age; maternal education; maternal racial/ethnicity; maternal tobacco use; maternal alcohol use; prenatal care, maternal marital status; maternal medical risk factors for this pregnancy, Medicaid status; preterm labor, preterm birth; and maternal weight gain during pregnancy). Less educated women (for 7 to 11 years of education, RR = 1.566, 95% Cl = 1.48 - 1.66); women with medical problems (for diabetes, RR = 1.104, 95% Cl = 1.021 - 1.193; for chronic hypertension, RR = 3.121, 95% Cl = 2.866 - 3.399; and for pregnancy associated hypertension, RR = 2.936, 95% Cl = 2.818 - 3.058); women with inadequate weight gain during pregnancy (for less than 17 pounds, RR = 3.337, 95% Cl = 3.17 - 3.51); those who were on Medicaid (RR = 1 209, 95% Cl = 1.177 - 1.242); those who used alcohol during pregnancy (RR = 1.628, 95% Cl = 1.468 - 1 805); those who had no prenatal care (for those who had prenatal care, RR = 0.432, 95% Cl = 0.402 - 0.464); women who had a preterm birth (RR =12 114, 95% Cl = 11.802 - 12 434); and women who had preterm delivery (RR = 9.816, 95% Cl = 9 572 - 10.066) were at a higher risk of giving birth to LBW infants than mothers without these risk factors. Women who were 20 years old or older were less likely to have a LBW birth Births who were male were also less likely to be LBW than female births (RR = 0 89, 95% Cl = 0.868 - 0 914) Before adjustment for covariates, non-Hispanic whites had the lowest risk for LBW, and nonHispanic blacks had two times higher risk than non-Hispanic whites. However, after adjustment for these covanates, Hispamcs had the lowest risk of LBW and nonHispanic whites had the highest risk The risk of LBW associated with maternal smoking also differed among the three racial/ethnic groups: non-Hispanic white smokers had the highest risk (OR = 2.033, 95% Cl = 1.874 - 2.205), non-Hispamc black smokers had the second highest risk (OR = 1.780, 95% Cl = 1.518 - 2.088), and Hispanic smokers had the lowest risk (OR = 1.721, 95% Cl = 1.470 - 2.016). Educating women and teens about the risk of maternal tobacco use and other risk factors for low birth weight is an important intervention for reducing the incidence of LBW. Further studies should also be conducted to better understand potential factors among Hispanic women that lead to a reduced risk for LBW compared to women from other racial/ethnic groups.