ABSTRACT
There have been several reports in which maternal nutritional status has been implicated
as either a mediating or moderating factor in the relationship between maternal cigarette
smoking and birthweight and perinatal survival. Also, there is evidence that the effects
of maternal cigarette smoking on both intrauterine growth and fetal viability are
more intense among women of lower social status. The well-maintained data set of the
Cardiff Births Survey from 1965-1977 afforded an opportunity to review these issues
among over 50,000 births in south Wales (the survey took place in Cardiff City through
1973 and subsequently included suburban areas of South Glamorgan). The major findings
were: (1) Smoking was much more common with descending maternal social status; (2)
among upper status women, smokers had similar or slightly greater mean Quetelet's
indices (kg/m2 ) than nonsmokers. Among lower status women, smokers were considerably thinner than
nonsmokers; (3) the greater the adiposity of the mother, the less the association
between cigarette smoking and depressed birthweight; (4) perinatal mortality was significantly
higher among heavy smokers (10 or more cigarettes a day) than among nonsmokers; and
(5) neither the decrease in birthweight nor the excess mortality associated with smoking
was greater among those of lower rather than upper social status, except among class
I women, among whom smoking was only minimally associated with depressed birthweight.
With the inclusion of the South Glamorgan suburban population in the survey after
1974, the excess mortality associated with heavy smoking dropped from 53 to 16%. This
marked drop in excess perinatal mortality could not be accounted for by population
differences in social class, age, parity, infant sex, history of past stillbirth or
neonatal death, or adiposity.
