Tobacco Smoke Exposure During Pregnancy Increases Maternal Blood Lead Levels Affecting Neonate Birth Weight

Magdalena Chelchowska 0 1 Jadwiga Ambroszkiewicz 0 1 Katarzyna Jablonka-Salach 0 1 Joanna Gajewska 0 1 Tomasz M. Maciejewski 0 1 Ewa Bulska 0 1 Teresa Laskowska-Klita 0 1 Jerzy Leibschang 0 1 0 T. M. Maciejewski Department of Obstetrics and Gynecology, Institute of Mother and Child , Kasprzaka 17a, 01-211 Warsaw, Poland 1 J. Leibschang Department of Obstetrics, Warsaw Medical University , Madaliskiego 25, 02-544 Warsaw, Poland To assess the effect of lead exposure from cigarette smoke on fetal growth, blood lead concentrations were measured using inductively coupled plasma mass spectrometry in 150 healthy pregnant women. Mean lead concentrations in plasma and whole blood were significantly higher in the smoking group compared with the nonsmoking group in each trimester of pregnancy (p< 0.001). Logistic regression analysis showed the highest impact of the number of cigarettes smoked per day for serum lead concentration (=0.238; p<0.05), while in whole blood, it was duration of smoking before conception (=0.297; p<0.001). Birth weight of the smoking mothers' infants was significantly lower (meanSEM, 3,19250.8 and 3,56949.6 g, respectively; p<0.001) and negatively correlated with lead levels in plasma (r=0.38; p<0.001) and in whole blood (r=0.27; p<0.001). Therefore, it is suggested that smoking during pregnancy increases lead concentrations in maternal blood. Fetal exposure to low doses of lead in utero may be a serious risk factor causing lower birth weight. - Cigarette smoking may be one of the most common sources of lead (Pb) exposure affecting the general population. Tobacco contains lead, which enters mainstream smoke and is inhaled by smokers [1]. It has been estimated that between 1 and 5 g of lead could be inhaled from smoking 20 cigarettes per day [2]. According to the World Health Organization (WHO), tobacco smoke from burning one cigarette could contain from 17 to 980 ng Pb [3]. Despite the fact that in the last years a decrease in the number of active smokers has been observed, cigarette smoking still plays a significant role among hazardous health-related behaviors. This is particularly disturbing for pregnant women. Epidemiology studies conducted at the Institute of Mother and Child indicated that in Poland between 25 and 30 % of pregnant women were active smokers and close to 60 % were passive smokers (home and/or occupational exposure) [4]. At present, acute lead poisoning has become rare but chronic low-level exposure to lead remains a public health issue. Chronic low-level exposure may result in lead accumulation in renal tubule, lung, hepatocyte, and calcified tissues. It is well-known that lead accumulates mostly in the bones of the body [58]. The body burden of lead stored in maternal bone can be released during pregnancy and contribute to fetal lead exposure since there is no protective barrier to the transplacental transport of lead [911]. Because the body burden of lead in smoking mothers is higher than in nonsmoking ones, lead in maternal bones may therefore be mobilized during pregnancy even if the mother has stopped cigarette consumption [5, 1113]. Elevated blood lead levels of pregnant women can be a risk factor for gestational hypertension/preeclampsia, spontaneous abortion, preterm labor, and premature rupture of the fetal membrane (PROM) [1417]. In addition, low-dose lead exposure in utero may have an adverse effect on birth weight and developmental delays in children [18, 19]. A variety of studies have shown that chronic low-dose lead can be associated with higher concentrations of this heavy metal in the blood of mothers and infants, but information on the effect of smoking on lead storage through pregnancy is limited [2023]. Therefore, the main objective of this study was to evaluate the effect of cigarette smoking on plasma and whole blood lead levels in pregnant women. The correlations between concentrations of lead and markers of estimated intensity of cigarette smoking (serum cotinine level, number of cigarettes/ day, duration of smoking before conception) were studied. The relationship between maternal lead status and birth weight was also determined. Materials and Methods This was a casecontrol association study, which examined the lead status of tobacco smoking pregnant women engaged in regular clinic visits in the Department of Obstetrics and Gynecology Institute of Mother and Child and the Warsaw Medical University, Warsaw, Poland. All pregnant volunteers were made aware of the objectives of the study and signed a written informed consent form. The study was carried out according to the principles of the Declaration of Helsinki and was approved by the Ethical Committee of the Institute of Mother and Child. One hundred and fifty healthy pregnant women were recruited for the study. Inclusion criteria were uncomplicated singleton pregnancies and the first trimester of pregnancy. Gestational age was estimated by the last menstrual period and confirmed by ultras (...truncated)