Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Symposium Abstracts: Symposia Presentations
Background and Objective:
Subtoxic blood lead levels (BLL) during pregnancy can be responsible for intrauterine delays in foetal development and thus increased risk of morbi-mortality of newborns. Since there is no protective transplacental barrier to lead, foetal exposure is due to maternal environmental exposure together with either increased absorption or bone demineralization with consequent release of lead, or both, that may occur during pregnancy. In non-occupationally exposed women, lead exposure may be increased due to residing near lead sources, consumption of polluted food products, and habits such as alcohol consumption and tobacco smoking. The main purpose of this study was to provide Portuguese data on the extent and pattern of foetal exposure to lead as determined through lead biomonitoring in the blood of pregnant women. Investigation on maternal BLL determinants and potential effects of subtoxic BLL on premature delivery and on newborn's characteristics was also objective of this study.
Materials and Methods:
BLL was determined before delivery, in a total of 791 pregnant women, primiparae or with last child ≥ 3 years, residing in two different Portuguese regions.
On average, BLL were not high (GM = 2.3 μg/dl), although 4.8% were μg/dl. BLL were significantly associated with residence region, smoking (before and/or during pregnancy), risky occupation, and being primiparous. Despite that smokers mean BLL (3.9 μg/dl) was significantly higher (P < 0.001) than that of non-smokers (2.5 μg/dl), smoking lost statistical significance in a multivariate linear regression analysis. However, results from multiple regression approaches for BLL and the above mentioned covariates on outcomes such as prematurity and each of the newborn's characteristics suggest that cigarette smoking before or during pregnancy makes significant and independent contribution to lower birth-weight.
These findings support the public health recommendation that women in fertile age should not smoke.