EFFECT OF CHANGES IN MATERNAL SMOKING-HABITS IN EARLY-PREGNANCY ON INFANT BIRTH-WEIGHT

Background. The inverse relationship between maternal smoking and infa nt birthweight is well documented. Aim. The aim of the present study w as to examine whether a change in maternal cigarette consumption in ea rly pregnancy affects the infant's birthweight. Method. A total of 598 0 women who presented to their general practitioners between 1976 and 1979 with an unplanned pregnancy and the babies resulting from these p regnancies were included in the study. Women were divided into four ca tegories: non-smokers, smokers, quitters and reducers. Results. In ter ms of mean infant birthweight, the non-smokers had a clear benefit ove r the smokers whose babies were 153 g lighter (P<O.OO1), and over the quitters whose infants were 39 g lighter There was also an advantage i n stopping smoking: the smokers had babies whose mean birthweight was 120 g less than that of the quitters (P<0.001). There was,no demonstra ble benefit from reduc ing cigarette consumption without entirely stop ping. Conclusion. These findings may have important implications for w here best to target health education.