Combating the effects of smoking during pregnancy

If women give up smoking before their fifth month of pregnancy, there is no negative impact on the size of their baby. However, babies from poorly educated mothers who smoke during pregnancy, do experience lasting harm, thus these mothers need more advice and support in the early stages of pregnancy. This is the central finding of new research by Emma Tominey, an occasional research assistant at the Centre for Economic Performance (CEP) at LSE.

In Maternal Smoking During Pregnancy and Early Child Outcomes, Emma Tominey found that mothers who smoke during pregnancy will have smaller babies – typically 5.4 per cent (6.5oz) lighter than other babies. But around half of this damage is because of ‘unobservable traits’ of the mother – including other health risks she might take, such as drinking alcohol, and her nutrition and knowledge of healthy behaviour. This suggests that mothers do need to quit smoking to improve the health of their child, but this decision must be taken simultaneously with general health improvements.

Additionally, the research found that the lasting harm to babies of smoking during pregnancy is greatest if the mothers have a lower level of education. Children born to mothers who left school at the age of 16 suffer double the harm for each cigarette smoked. Yet it is not too late to help women who have smoked in the early stages of pregnancy – surprisingly, the research shows that the harm to the baby is essentially reduced to zero if the mother changes behaviour during pregnancy, including quitting smoking by month five of the pregnancy, longer than previous research has suggested.

Possible causes for this finding could either be that the harm from smoking accumulates during the final months of pregnancy, or because the mothers who quit smoking simultaneously reduce their health risks in other ways. Either way, this tells us that there is more time than we thought to help the mothers change their behaviour during pregnancy. Overall, the research suggests that while stopping mothers smoking during pregnancy is important, it is only half the battle. This study shows that in order to lower the incidence of underweight births, stopping a mother from smoking must be combined with helping her to be healthier in other areas of her life.

Emma Tominey said: "We find a really strong penalty from smoking for the entire nine months. It's really important that mums keep trying to quit smoking, because they can still improve the health of their child." She suggests that policy should be targeted towardslow educated mothers who are more likely to smoke.

Further, as smoking during pregnancy is linked with other ‘unobservable’ traits of the mother, to improve child health mothers should receive advice not just on their smoking habits, but on other health related areas of their lives. The government must also target its anti-smoking policy directly at poorly educated families.

For more information visit http://cep.lse.ac.uk/_new/
publications/series.asp?prog=CEPCP

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