Pregnant women who smoke can transmit a carcinogen to their unborn babies.

In a study of infants conducted by the University of Minnesota Cancer Centre, the first urine samples from 48 babies were analysed in a blind trial. One of the strongest carcinogens in tobacco smoke, NKK, was present in nearly 71 per cent of the samples obtained.

NKK is unique to tobacco, and its link with smoking mothers was underscored by the fact that none of the samples from the babies of non smoking mothers contained any NKK.

Commenting on the findings Gordon McVie, clinical director of the Cancer Research Campaign in Britain, stated that the evidence was pretty conclusive and that the levels of carcinogen in the babies were "worryingly high". He said the babies are "...presumably excreting these chemicals into the amniotic fluid and this is recirculated. It's like one long tissue culture experiment" (BMJ, 1998; 317: 555).

Keeping your home tobacco free may also help reduce the risk of sudden infant death syndrome (SIDS), according to Swedish researchers. Autopsy results on 24 SIDS babies showed that all but two had substantial amounts of continine, a nicotine by product, in their blood. Acute, heavy exposure to cigarette smoke may precipitate death from SIDS in vulnerable infants, the study concludes (J Ped, 1998; 133: 232-6).