Smoking in Pregnancy

Looks like it\’s not as bad as we are told:

The report uses data from the UK National Child Development Study, which provides details of mothers and their children between 1973 and 2000 — a total of 3,368 women and 6,860 children.

The information includes the mothers’ smoking habits, information about their families, and the birthweight and gestation period of the children.

Analysis of the data shows that smoking throughout pregnancy reduces birthweight by 5.6 per cent, and the gestation period by just over a day. But when the results are corrected for other factors, such as diet, lifestyle and alcohol, the effect of smoking on birthweight drops to 1.8 per cent and the reduction in gestation becomes insignificant.

A rule of thumb from many years ago: each cigarette smoked per day reduced, on average, the birth weight by 5 grammes. As a healthy baby is in the 2.5-3 kg range, 10 fags a day reduces birth weight by what, 2%?

13 thoughts on “Smoking in Pregnancy”

  1. This does rather assume that reduction in birthweight is the only damage done by the mother smoking.

    I think there is considerable evidence of chromosome damage and of later behavioural difficulties of children born to smoking mothers.

  2. I would have thought that the largest health gain is that quite a few women manage to give up smoking permanently courtesy of giving it up temporarily during pregnancy. The number must be considerable because I’ve known a few.

  3. HJ if the evidence of smoking causing the problems you mention is considerable you won’t mind posting references to it so we can check them out will you.

    Blaming everything on smoking, and other politically incorrect behaviours has become the default health policy in this country. It’s the triumph of propaganda over science. The tragedy is that worthwhile research is not done as the outcomes have already been decided.

  4. Ian Reid – a simple Google search will demonstrate that there is considerable, although not conclusive, evidence of smoking causing problems other than low birth rate.

    My point was that this study only considered birthweight – as if that were the only damage that could be done.

    Unlike you (who clearly have a bee in your bonnet), I was not commenting on health policy in this country. I was merely pointing out that this study (or rather study of studies) didn’t look beyond birth weight, so no conclusion on overall negative effects (or the lack of negative effects) of smoking during pregnancy can reasonably be drawn from it.

  5. “even though these mothers all smoked less then 2 packs per day”

    an odd “even though” there – I’d suggest that someone who smoked 39 cigarettes a day was quite a heavy smoker…

    also, it seems likely that the Tucker study above doesn’t correct for lifestyle factors – you’d need to repeat Tominey’s work but looking at genetic damage instead of birthweight.

    [chances of HJ coming up with something other than random “I know best” unsubstantiated invective: low. and to forestall any cheap shots, I always substantiate my invective…]

  6. john g:

    “I always substantiate my invective…”

    A sense of humour, at last. Or perhaps self-delusion. Pity about the continuing lack of manners or intelligence.

  7. wonder who this “john g” character might be? (when it comes to picking up on trivial errors that don’t obscure the piece’s meaning, I adopt a tit-for-tat strategy).

    also, where do you get off re “manners”? this is an internet comments section, not tea at the Ritz with your granny. if someone says something idiotic and/or unsupported, they deserve a merciless slating. See Captain Middleton’s approach

    The facts in this particular case are:
    1) many studies have found a correlation between smoking and low birthweight
    2) many studies have found a correlation between smoking and other defects in the baby
    3) a metastudy of 1 shows that actually, most of the effects attributed to smoking on birthweight are due to other environmental factors.

    This doesn’t logically imply
    4) a metastudy of 2 would show that actually, most of the other effects attributed to smoking are due to other environmental factors.

    …but it sure as hell makes it sound like a plausible hypothesis to investigate. Agree? Disagree? Understand the question?

  8. HJ you’re right I do have a bee in my bonnet. Considerable, but not conclusive evidence, is still inconclusive. Ian Bennet that is a link to a grant being given to make a larger study. Strangely there are no reports of the results of that larger study on the internet. Is this an illustration of publication bias, a phenomenon documented here http://www.numberwatch.co.uk/publication_bias.htm

  9. Tim, why are you so interested in defending smoking mothers and smoking in general? Smoking is one of the most damaging things we can do. Do we need to know anymore than this? It makes me laugh when right-wingers decry first trimester abortion, yet condone smoking during pregnancy. What a mixed up weird world some people live in!

    Tim adds: “so interested in defending smoking mothers and smoking in general” Gosh Neil, I dunno. It could be because I think that we’re being lied to, it could be because I’m concerned with civil liberties? If you have a look around here you’ll see that those are indeed two bees in my bonnet. I rail about the stupidities of drugs legislation just as much as I do about smoking, and on the same joint grounds: there’s a civil liberties aspect and also we’re being lied to.

    BTW, please try and get it correct. I’m not right wing, I’m a liberal.

  10. Tim,

    As you well know, I agree with you on the civil liberties issue when it comes to smoking or whatever. It is no business of the state to try to alter our behaviour in order to ‘protect’ the NHS. The better solutions is for us to face the consequences ourselves.

    The issue I have with your approach is that you jump on a report like this to support your case. It doesn’t. Why? Because had the report said that there was a clear and dramatic link between smoking during and low birth rate would you (conversely) have taken this as a justification for the state to interfere in civil liberties? Of course not.

    In other words, it shouldn’t matter what the effects are on the NHS if you believe in civil liberties.

    Tim adds: Neatly avoiding my second point, which is that I think we’re being lied to.

  11. Tim,

    Exactly who is lying? You might think that the information propagated on this subject is wrong, but that ‘s not the same as lying (lying requires a deliberate attempt to deceive).

    Your comments could also be regarded as intended to deceive, as you omitted to mention any other possible effects of smoking in pregnancy other than low birth weight. I don’t think you had any such intention, but you have drawn a conclusion based on insufficient evidence – which is pretty much what you have accused others of doing.

    After all, I have seen you trumpeting the infamous Philip Morris report from the Czech republic in support of the assertion that smoking is actually beneficial to the public purse. It doesn’t take much reading of this report to realise that it is full of serious flaws (all, curiously, in favour of the assertion it was designed to support) and that it was designed specifically to deceive.

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