To the Editor: Helping pregnant women to stop smoking and not to resume after their baby is born is a key target for smoking prevention. Pregnancy (or trying to become pregnant) is a time when women are motivated to stop smoking for the sake of the baby and they are in contact with healthcare professionals who can help them do so.

We have calculated the impact of smoking during pregnancy in terms of deaths, hospital separations and costs to the healthcare system, and estimated the extent to which these effects could be reduced through interventions initiated by healthcare professionals as part of routine clinical contact.

We considered the following conditions: pre-eclampsia (which is less common among smokers), low birthweight (including hospital costs for the mother and the baby, and infant deaths), premature rupture of membrane, spontaneous abortion, ectopic pregnancy, placenta praevia (including infant death), and sudden infant death syndrome (SIDS). We used estimates of relative risks (RRs) for these conditions for women who smoke during pregnancy (or, for ectopic pregnancy, for women who might become pregnant) from meta-analyses.1-3 We obtained data on deaths,4 hospital separations,5 and costs to the healthcare system6 for 2001–02. The prevalence of smoking among pregnant women of all ages in New South Wales since 1994 has been in the range 17% to 22%.7 The prevalence of smoking among all women of child-bearing age in 2001 was about 28%.8 From these data, we calculated attributable fractions1,2,9 for average values (using point estimates for RRs and 20% for prevalence of smoking in pregnancy) and extreme values (using the 95% confidence limits for RRs and 17% and 22% for smoking prevalence).

In summary, the average number of adverse events attributable to smoking each year in Australia are: infant deaths, 78 (extreme values, 66–87); hospital separations, 6890 (extreme values, 4130–9450); costs to the healthcare system, $23 million (extreme values, $16–$29 million).

A Cochrane review of behavioural (not pharmacological) interventions for stopping smoking in pregnancy showed an absolute reduction of 6% (95% CI, 4%–8%).10 Thus, if the prevalence of smoking during pregnancy were reduced from 20% to 14%, we calculate that there would be 20 fewer infant deaths, 1600 fewer hospital separations, and a saving of $5 million to the Australian healthcare system per year. (Details of the calculations can be obtained from the authors.)

These gains could be realised by increasing community awareness of the risks of smoking in pregnancy and helping health professionals to use smoking prevention strategies in their routine encounters with pregnant women.