[Effects of environmental tobacco smoke on prenatal development. (Review of the medical literature)]

Abstract

For near thirty years, epidemiological studies have coped with the search of possible noxious consequences of an involuntary exposure of pregnant women to environmental tobacco smoke on the gestation and the intrauterine development of embryo and foetus. These studies were mainly retrospectives; a careful study of the methods used (questionnaires, evaluation of exposure, and so on ...) gives evidence that they can rarely avoid serious criticism. As possible effects of intrauterine exposure to environmental tobacco smoke, low birth weight and impairing of other body parameters, perinatal mortality, frequency of abnormalities have been reviewed. As a potential cause, the role of the father tobacco smoking has been especially examined. As a whole, the consequences of a prenatal exposure to environmental tobacco smoke are an extremely controversial subject and no obvious effect has yet been universally recognized. The critical analysis of the studies has shown that, frequently, the epidemiological studies have been interpreted in order to find links between and involuntary exposure to tobacco smoke and some troubles of reproduction, particularly in offspring. As a matter of facts, fundamentally, the noted actually correlations, even if they are statistically significant, are not able to move such links. They are only able to indicate the existence of an association and only, if the eventual role of confounding factors has been properly treated. An interesting case is the potential effects of the father's tobacco smoking. The hypotheses emerging from these examined inquiries remain to be more precisely defined and thoroughly by new studies, preferentially prospective, and, when necessary, completed by animal experiments. It is suggested that a special effort shall be applied to the measurement of the exposure of pregnant women to define toxic compounds originating from environmental tobacco smoke. Presently, it is not possible to draw a conclusion on the noxious or innoxious influence of the involuntary exposure of pregnant women to environmental tobacco smoke, particularly as far as potential risks for foetus are concerned.