Smoking and Reproduction

Abstract

Despite the now overwhelming evidence of the ill effects associated with smoking during pregnancy, this practice has continued and even increased during recent decades. An urgent need exists for all who attend this First International Congress on Maternal and Neonatal Health to promulgate a number of simple principles and facts on smoking and health to women throughout the world. Environmental agents known to deviate heritable cellular characteristics from optimal normal are mutagens--ionizing radiation, certain chemicals, and viruses--with capacity for increasing heritable differences among cell populations of tissues. Many carcinogenic agents were identified in tobacco smoke by earlier animal assay methods of measurement, and recent application of newly developed short-term tests of mutagenicity has demonstrated that a high proportion of these carcinogenic compounds are mutagens. The most notable mutagen identified in tobacco smoke remains the radioisotope, Polonium 210, a volatile alpha particle emitter and a most powerful contact mutagen, which has been consistently identified in tobacco smoke in the respiratory mucosa and urine of smokers. Transport of such mutagenic agents from the respiratory tract to the urine necessarily occurs via the blood stream, and germ cells as well as somatic cells are inescapably exposed to the blood borne mutagens. Likewise the embryo and fetus are exposed to damage by mutagens and other harmful substances entering the circulation of pregnant women who smoke. Inhalation of smoke exposes the entire body of the smoker to genetic damage. How much of the rise in malformations and malignancies can justly be ascribed to tobacco is unknown. An attempt was made by the author and coworkers some years ago to measure the effects of smoking upon reproduction generally and the possible contribution of smoking to congenital malformations and childhood leukemia in Seattle. Data were obtained by public health nurse telephone interviews from mothers of 2023 infants born in Seattle during 1964, from mothers of 164 children hospitalized with diverse congenital malformations, and from mothers of 57 children with leukemia. The findings did not demonstrate a striking relationship of congenital malformations and childhood leukemia to the smoking experience of their parents, but the data patterns did suggest a clustering of children with leukemia to women who smoked most heavily during the index pregnancies. Apparently large proportions of women delivering in European countries and the US smoked during their index pregnancies, with highest maternal smoking in Scotland with 36.7%, Ireland with 35.8%, and Sweden with 34.0%.