One of the most infuriating examples of conflicting evidence and advice is on the subject of paracetamol in pregnancy. The NHS guidelines say, “Paracetamol has been used routinely during all stages of pregnancy to reduce a high temperature and for pain relief. There is no clear evidence that it has any harmful effects on the unborn baby. However, as with any medicine taken during pregnancy, use paracetamol at the lowest effective dose for the shortest possible time.” What exactly does this mean? If paracetamol is safe in pregnancy, then why limit the dose? Why worry pregnant women into putting up with their headache / hip pain / backache for no good reason? If paracetamol isn’t safe, and there are risks associated with it, why tell women that it’s OK to take it during pregnancy? Why not give us the facts so we can make an informed decision? It really does seem negligent to put out such vague advice that women are left with a choice between putting up with the pain, just in case, or taking pain killers and risking unknown consequences for their unborn baby. When I was pregnant I assumed that paracetamol were perfectly safe and that the cautious advice was just another example of overly conservative recommendations. It got to me though – I did try to avoid paracetamol, and regularly ranted about having to put up with headaches without an evidence-based reason to do so.
A few internet searches later, it seems that there is some evidence for a link between paracetamol use in pregnancy and childhood asthma. A 2011 systematic review found that “the use of paracetamol during pregnancy is associated with an increased risk of childhood asthma”, and concluded that more research is urgently needed. A Danish study, published in 2012, also indicates a link, and a 2010 British study suggests that the link between paracetamol use and asthma is unlikely to be due to confounding variables. These studies can only show an association though – they didn’t randomly assign women to take paracetamol or not, and so they can’t prove that the paracetamol caused the asthma. Maybe the pain that caused the paracetamol use caused the asthma? Knowing all this, I can see why the advice on paracetamol is cautious – but really, why couldn’t a medical expert summarise the evidence and let me make my own decision? Why am I trawling journals, which aren’t always open access (available without subscription), trying to make sense of the evidence for myself? Argh.
Evidence-based rants 