Tag Archives: decision-making

Giving birth after a caesarian delivery

We are due our second child in February next year (a 20-month gap between no.1 and no.2 – yes, I’m weary just thinking about it). I shall spare you the warts-and-all birth story, but our first baby was born by caesarian section after a worrying dip in his heart rate.

There are two options for women in this situation. The first is to choose to have a caesarian delivery again, which is known as “elective repeat caesarian delivery”, or ERCD for short. The second is to have a “vaginal birth after caesarian”, often abbreviated to VBAC. The actual process of attempting a VBAC is called “trial of labour after caesarian”, or TOLAC.

If we were living forty years ago, there wouldn’t be much debate – we would have been booked in for a C-section. This started to change in the 1980s as more women and couples pushed to have a more ‘natural’* vaginal birth, which led to an increasing number of VBACs. This was backed by improving caesarian surgery, such as a change from making the incision ‘up’ the belly (‘longitudinal’) to making it ‘across’ the belly (‘transverse’) to achieve more effective repair, as well as advice from leading health organisations to reduce caesarian rates.

It seems that in the UK, however, as in many other countries, caesarian deliveries after previous caesarians are back on the increase. One reason is the real fear that the uterus, weakened by the surgery, even by a transverse section, might rupture if a vaginal birth is attempted. A ruptured uterus can lead to complications for the mother and child (more on the specifics in a minute).

There are currently no randomised trials to compare the risks associated with two approaches and most studies have looked retrospectively at what happens in ERCDs or VBACs. This means that it’s hard to inform women before they give birth what the different risks might be.

An article in the scientific journal PLOS Medicine earlier this year – ‘To VBAC or Not to VBAC‘ by Catherine Spong – summarised two research papers that were published at the same time. They both capture information on what the mother intended to do, as well as what actually happened. This gives some relevant insight into whether preferences were successfully carried out, and what the true risks are for women planning either an ERCD or VBAC.

And good news, there’s no paywall so access is free!

The headline message for the woman is:

…risks such as uterine rupture are higher for women attempting a trial of labor following a previous cesarean delivery than those having an elective repeat cesarean delivery; however, the overall risks are low in both groups.

So how does it break down?

The mother

One study was based in the UK and the other in Australia, and both calculated that the uterus ruptures in approximately 2 in 1,000 planned VBAC cases and 1 in 1,000 planned ERCD cases. These figures are lower than those previously reported and communicated to patients, which range from 4-12 ruptures in every 1,000 women planning VBACs. The authors of the Australian study put this down to the hospitals following standardised treatment plans that were designed using the latest evidence. Either way, the results are encouraging.

The British study also found that the risk of rupture is higher for women who have had two or more previous caesarean deliveries, less than 12 months since their last caesarean section, or whose labour was induced (up to roughly 6 in every 1,000 cases, if I’ve calculated correctly, so still relatively low).

As for how the intended modes of delivery played out, nearly 98% of women who planned an ERCD succeeded, but only 57% of those who planned a VBAC did. Almost 25% of women originally planning a VBAC ended up choosing a caesarian delivery, which suggests they either changed their minds or doctors advised that a caesarian should be carried out instead.

The baby

The Australian study also assessed the outcomes for the babies. The researchers recorded fewer serious problems for the babies in the ERCD group when compared with the babies in the VBAC group – approximately 1 in a 100 ERCD births had difficulties, whereas over 2 in a 100 VBAC births had problems for the baby. Serious problems that needed treatment included physical birth injuries, infection and low oxygen in the umbilical cord.

There were two stillbirths in the VBAC group, but as Catherine Spong explains in the summary piece, there’s an important caveat to note. Elective caesarians, by their nature of being chosen, happen at a set time – in the Australian study the C-sections were performed, on average, after 38.8 weeks of term. Laboured vaginal births, by their nature of being involuntary, cannot be booked in, and the average time that these took place was at 40 weeks of term. As a result, it is uncertain whether these stillbirths were associated with the type of delivery or the extra time in the womb (or, even, that they happened by chance – 2 is a very low number from which to draw conclusions).

The state of play

Uterine rupture can increase the risk of stillbirth. According to statistics cited in Spong’s article from the National Institutes of Health in the US, infant death occurs in 6% of cases of a ruptured uterus – given the rates of rupture reported by these two studies, it puts the estimated risk somewhere in the region of 3 deaths every 50,000 ERCDs and 6 deaths every 50,000 VBACs.

Uterine rupture can also increase the risk of brain damage to the baby due to a lack of oxygen (‘hypoxic-ischaemic encephalopathy’, or HIE). Another review estimated this risk to be one in every 1,250 VBACs against practically zero risk in ERCDs.

However, these ever-so-slightly higher risks of complications in VBACs need to balanced against other potential problems associated with caesarian deliveries. Serious infant respiratory problems are more common in elective caesarians (observed to be 3-6 in 400) compared with vaginal deliveries (observed to be 1 in 400). Newborns are also more likely to be admitted to the neonatal intensive care unit (NICU) due to the need for ventilation therapy and more likely to spend longer than seven days in hospital. Other caesarian-specific risks to the mother, such as dislodged blood clots, need for a blood transfusion, extended wound healing, a longer stay in hospital and future pregnancy complications, are also present.

The extent of some of these risks is greatest in the cases of caesarian sections following failed VBACs, which means understanding which women are most likely to have a successful VBAC is hugely important. A group of US clinicians highlighted various factors that increase the likelihood of a successful VBAC: women with one previous caesarian delivery with a low transverse incision, women who at some point have had a prior successful vaginal delivery, and women who had their caesarian because the baby presented breech or some other form of malpresentation rather than for other reasons. Vaginal births in general are more successful when women have access to high level of healthcare, something we should always seek to protect and improve wherever necessary.

Other factors decrease the likelihood of a successful VBAC: failure of the labour to progress or baby to descend during a previous TOLAC, a higher age and weight of the mother, and preexisting medical conditions such as hypertension or diabetes.

And, so…?

What does all this population data mean for the individual woman? The risks for TOLAC seem reasonable in the context of the inherently uncertain process of labour, but women should be properly prepared and counselled to understand the benefits and risks. This should ideally be done with full reference to real numbers and so that the discussion takes the individual’s status into account. That way, the chances of a satisfactory outcome for mother, child and doctor can be at its greatest.

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*I hesitate to use natural to describe vaginal births: ‘natural’ has so many connotations about medical interventions and vaginal births vary from case to case, which renders ‘natural’ a bit of a messy description.
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Milking the (cash) cow?

Or, should I feed my one year old cow’s milk or infant formula?

The Skeptical Son is about to hit one year of age, which brings a few landmarks with it. MMR vaccination, standing up (albeit a little precariously), and a move from specialised (breast or infant formula) milk to regular, unmodified cow’s milk.

This latter point seemed pretty uncontroversial. The UK National Health Service and the American Academy of Pediatrics both recommend feeding cow’s milk to a baby beyond 12 months. The NHS explicitly states: “Infant formula, follow-on formula or growing-up milks are not needed once you baby is 12 months old”.

So I was intrigued to see infant milk formula products specifically targeted at the over one year olds, such as Aptamil 1+yr & 2+yrCow & Gate 1-2yr & 2-3yrHipp Organic growing up milk (from 12 months), and SMA 1-3yrs.

A look at the scientific literature, in line with the NHS and AAP guidance, backs up a move to cow’s milk at 12 months. Unmodified cow’s milk is not recommended before this age because it contains high levels of sodium, potassium, phosphorus, and calcium, and lacks vital nutrients, such as iron, vitamin C, and linoleic acid. As a baby’s diet becomes more varied and complex by the age of one, many of the nutrients previously gained from milk (breast or modified cow’s formula) is obtained from food. An infant can, in most cases, safely move to consuming cow’s milk, and it is only if a specific deficiency develops that they will need targeted supplementation.

http://www.flickr.com/photos/jelles/2902422030/

Cow by JelleS [CC-BY-2.0]

The NHS’s health information leaflet, however, says: “It is recommended that all babies aged from six months to 5 years are given a supplement that contains vitamins A, C and D, unless they are drinking 500ml (a pint) of infant formula a day (infant formula has vitamins added to it)”. This then brings us back to enriched infant formula.

The infant formula manufacturers appear obliged to acknowledge that breast milk is recommended for young babies (see disclaimer notice*), consistent with the World Health Organization’s guidance. All of them, though, promote their 1 year+ products as, variously, enriched with iron, vitamins C & D, GOS/FOS prebiotics and omega fatty acids. Advertising claims include milk formula that is “nutritionally superior” to cow’s milk, “has been specially developed to help meet the nutritional needs of toddlers”, and will “encourage your toddler’s natural friendly bacteria to thrive”.

So now I’m a little torn. Anaemia, avitaminosis and lactose intolerance are, evidently, serious conditions that need to be addressed, and products need to exist for these cases. But the marketing doesn’t seem in line with the healthcare advice: without looking into it, I was initially left with the impression that the specialised infant formulas represent the gold standard, containing everything that is needed to support my son’s “amazing development” [© Cow & Gate]. The adverts and packaging don’t suggest these products are for cases where a deficiency has been identified, rather it appears to play to the ‘don’t take any chances’ or ‘be on the safe side’ worry of parents. SMA, for instance, says “it is hard to know if they are getting all of the right nutrients they need at this important time”.

I guess this speaks to a wider problem with nutritional supplements, ‘superfoods’ and enriched dietary products, some of which make all manner of claims about health and well-being (see Andy Lewis’ Quackometer for more ‘Confusopoly of Diet’).

Anyway, now for a quick look at money, something that’s precious to many families. A 900g tub of Aptamil 1+ yr costs £8.49 (Sainsbury’s price). This means that a daily intake of 500ml will cost 79p (83.3g formula). An equivalent daily portion of whole cow’s milk costs 26p. Even adding in a multivitamin supplement works out at an extra 13p a day. Over a week this difference amounts to £2.80; over a year it’s a saving of around £145.

I should emphasise that the post-one year milk formulas seem completely legitimate products to sell and I’m far from claiming a conspiracy, but I explore it here simply to question whether their advertising is a little misleading. Of course, dietary products claiming all sorts of health benefits is not a new or isolated phenomenon, but I worry that the baby market particularly plays on the anxiety of parents that inclines them to prove themselves as perfect guardians.

Maybe I’m being overly cynical in suspecting that the manufacturers are being unreasonably opaque. Perhaps I’m too naïve in wishing that promotion of products that affect ours and our babies’ health was more honest. Would it be regulatory overkill to make infant formula products, in the same way as the breastfeeding disclaimer, carry an objective notice about cow’s milk and the current healthcare advice?

And on that ambivalent note, I shall end.

*The common wording across manufacturers’ websites and the prominent positioning of the statement (it is displayed any time one tries to click through to a product for the first time) suggests this is a statutory requirement. This would be interesting if it is, so any light that anyone can shed on this would be appreciated!

“It must be his teeth”: teething symptom myths

I wrote some time ago about how our little one was teething and the measures we’d taken to alleviate his discomfort. Well, this little chapter is still in full swing, with a mere two teeth erupted so far. But this isn’t a place to write long diary entries detailing my child’s progress; instead, I want to bring some science to light.

I’ve heard a number of physical signs regularly attributed to teething, such as rosy cheeks, diarrhoea, green faeces, fever, gnawing, irritability and drooling to name a few. It seems these beliefs are fairly common, as surveys of parents and health professionals have shown.

It gets interesting, however, when you look at some of the research done in this area. There seems to be some disagreement over which symptoms are actually caused by teeth eruption, and whilst it’s clear that individual babies will display different teething signs, it’s also apparent that some beliefs are not borne out by the evidence.

One of the difficulties is that the onset of teething (6-12 months) often occurs around the same time that babies become particularly susceptible to a variety of infections and upsets. This is mainly due to the decline in immunity imparted by maternal antibodies, as well as changes in behaviours that see infants actively interact with their environment.

There certainly seems a fair amount of evidence that many signs assumed to be caused by teething are actually caused by something else, such as meningitis, bacterial infection and herpes simplex virus infection. As the NHS Clinical Knowledge Summary bluntly puts it: “Teething does not cause children to become systemically unwell”. 

Another problem is our familiar foe: limited experimental design. Studies in this area are rather limited in number, often rely on self-reporting rather than objective measurement, deal with correlations not causations, and many look back at clinical data rather than tracking babies as they develop. These complications may be exacerbated by the fact that many health professionals hold erroneous beliefs too, which influences the data collected.

So what do we know?

Symptoms often misattributed teething:

  • Diarrhoea: This is one of the most common symptoms attributed to teething, but no solid data exist to suggest this is due to teething in the majority of cases. It has been tentatively suggested that slightly looser stools may occur during teething and this could lead to mild nappy rash.
  • Fever: Teething may cause a small rise in body temperature, but a feverish temperature above 38°C is unlikely to be due to teething.
  • Runny nose: The jury’s out on this one, but the reported associations are weak and this symptom is more likely to be a due to a wider problem.
  • Wakefulness: While teething may cause some disruption of sleep, this is probably over-exaggerated by parents, and may be partly down to changing sleep patterns and the formation of attention-seeking habits. I was also told by a midwife that teeth move more during the night, causing greater wakefulness – I initially thought not, as it seems more reasonable that the distress is apparent when there isn’t anything to distract the infant. Any data on this latter point would be gratefully received!
  • Green faeces: This is one I’ve heard a number of times, sometimes with an explanation of a change in the stomach acid balance. I can’t find anything in the literature (but please come forth and proffer!) but, on the face of it, it doesn’t seem to chime with idea that teeth eruption does not cause systemic upset.

 Symptoms more likely to be caused by teething:

  • Drooling: Excessive saliva can form and this may be seen by an infant dribbling more than usual. This isn’t conclusive, though, as salivary glands become active around 2–3 months of age and constant drooling can be expected then.
  • Gnawing: Teething infants may gnaw on cold, hard objects or on their fingers to temporarily help with teething discomfort.
  • Mild irritability: The pain associated with teething, which is mostly associated with an inflammatory response within the gums, might cause grizzliness, disturbed sleep, ear rubbing and a decreased appetite.
  • Rosy cheeks: This is some support in the literature that flushed, red cheeks are associated with teething, although this is not clear-cut.

As I said earlier, different babies will experience different symptoms and it’s worth bearing in mind that no single symptom can definitively ‘diagnose’ teething.

Many of these beliefs appear to have some root in history as far back as Hippocrates in the 4th century, when teething was thought to be a deadly disease (“dentition difficilis”, Latin for ‘difficult teeth’). Teeth eruption, it was believed, caused a disturbance in the infant’s nervous system, leading to severe systemic upset. This was, again, most probably due to coincidental timing of onset of teeth eruption and an increased likelihood of serious infection, which in those days often led to infant death. Worse still, many of the treatments used for teething right up until the 19th century were actually toxic, such as opiates, lead, mercury salts, bromide and salt.

So while some studies have suggested that teeth eruption is associated with certain physical symptoms, none has really been able to establish causal relationships, and others have found no associations at all. It may be that a diagnosis of teething can relieve parents’ anxieties about an upset infant. Understanding true causal factors, however, is important to prevent misdiagnosis – attributing symptoms to teething could miss more serious conditions that require immediate medical attention.

P.S. I was hampered in my access to a lot of the research in this area, and so if I’ve missed anything then please let me know. A good argument to support Open Access publishing!

Is breastfeeding all it’s cracked up to be?

Zoe Williams wrote an intriguing article in The Guardian that challenged some widely held assumptions and beliefs about the benefits of breastfeeding (‘The backlash against breastfeeding’). It did, as you might imagine, generate strong reactions from those who vehemently espouse that “breast is best”. It was written on the back of a recent front cover of Time magazine that caused an even greater furore (‘Are you mom enough’), which championed a form of ‘attachment parenting’ that encouraged breastfeeding until the child is well over one year old.

I did feel that Zoe Williams’ article raised some interesting points, some of which I wanted to address here.

But I also had the strong suspicion that the claims made for [breastfeeding’s] benefits – the higher IQ, the protection against obesity, the superior bonding, the warding off of disease both now and for ever, both for baby and for mother – were mostly bogus. A lot of the reasoning seemed syllogistic (babies born into low-income families end up fatter; low-income mothers breastfeed less than high-income mothers; therefore breastfeeding prevents obesity) or frankly lame.

This relates to the concept I’ve written about before, that correlation does not imply causation. As she quotes Joan B Wolf later in the article: “Breastfeeding cannot be distinguished from the decision to breastfeed, which could represent a more comprehensive commitment to healthy living.”  

While this is true, that is not to say that the researchers who conduct these types of observational studies are not aware of this limitation. It is hard to do interventionist, controlled studies, as you would do in a lab or in randomised controlled trials to test a new medicine. Imagine randomly assigning new mothers to one of two groups – breastfeeding or formula-feeding – and getting them to stick to this regimen so that you can measure the outcomes of the children. Not likely, which is why such interventionist studies have been limited (1 & 2).

So researchers work with the tools available to them. They try to include appropriate comparator groups and make statistical adjustments to account for potential confounding variables. Not perfect by any stretch, but the best available methods.

I knew a lot of mothers who formula fed; they didn’t seem to love their babies less.

Ignoring the submission to anecdote, which is a mortal sin to evidence-based thinkers, a more worthwhile point to address is an argument I’ve often heard that goes approximately: “Well, they say breastfeeding is best, but I formula-fed and my child turned out alright”.

There are two key flaws in this reasoning. One is that by advocating breastfeeding, it is implying that formula-feeding is bad. No. It’s just there’s less chance that any outcomes associated with breastfeeding will also be seen with formula-feeding. The second misconception is that there’s a complete separation, or dichotomy, between the two groups. But here we’re comparing averages of large study groups – there will be huge amounts of variability around the averages and a lot of overlap, and only the right statistical analyses can reveal any true differences.

Put simply, there will be mothers of formula-fed babies who form strong attachments (to carry on the example in the article) and mothers of breastfed babies who do not.

By analogy, there will be some people that do all the ‘right’ things – not smoke, eat healthily, exercise, apply sun cream – who will get cancer and there will those who smoke 40-a-day and drink to excess who do not. It doesn’t disprove the link, it’s all about stacking the odds in your favour.

(I should clarify that the evidence I’ve seen for superior bonding associated with breastfeeding is somewhat weak, but I referred to it here to address a more general point about the common use anecdotal evidence).

This struck me as a bizarre place to have arrived at; where even to talk about the evidence behind the benefits of one type of infant feeding over another is heretical.

Absolutely correct. We should constantly gather and scrutinise data, and if strong enough evidence emerges that contradicts our prior assertions, then we should be prepared to change our minds. I applaud the fact that this article was written, even if there are bits I wouldn’t necessarily or wholeheartedly go along with, as we should always be ‘talking about the evidence’.

The questioning of the orthodoxy is taken as a direct attack on babies.

[Charlotte Faircloth, sociologist]: “… Everything has got very heated, and very moralised. How you feed your kids is no longer a personal decision. There’s this idea that you can breastfeed your way out of poverty, or if you don’t breastfeed your kid’s going to be fat or have a low IQ…” She pauses. “It’s all got a bit out of hand.”

Williams is right that some breastfeeding advocates are evangelical and overly ideological about breast milk, to the point that some mothers feel over-bearing pressure to breastfeed. As Charlotte Fairclough is quoted, it’s a personal decision. Fairclough also touches on my earlier point that there’s no binary distinction in the outcomes of children who are breastfed and those who are not – breastfeeding doesn’t determine the outcome but may make it more probable (and, if it does, it will certainly still only be one factor amongst many).

Williams then quotes French feminist Elisabeth Badinter:

“when it’s recommended that you breastfeed your child for one year – six months exclusively, with nothing else, day and night, on demand – there are obviously consequences for a couple.”

“There are women for whom breastfeeding is a true pleasure. It’s very good for them and it’s very good for the baby. But to breastfeed a baby if the mother herself doesn’t like it? It’s a catastrophe. The decision to breastfeed is an intimate and private decision. No one should be able to interfere.”

In my mind, this touches on something I have written about before – that to lay down a hard-and-fast prescription for parents to follow is not always straightforward or productive. A more nuanced approach is often required that takes into account the familial circumstances and considers the parents’ well-being as well. It would be no good hectoring parents to follow a particular path, if it leads to a significant worsening of their own physical or mental health, especially if the knock-on effect is a deterioration in family relationships.

It seems highly unlikely that this would allow people to be good parents nor provide a decent environment for the child (a brief look at the scientific literature suggests this assumption isn’t entirely unreasonable, e.g. thisthis and this). It also risks attaching blame to a parent for any perceived character flaw in their child, and guilt-tripping parents in this way seems a counter-productive approach.

The research about ear infections, respiratory disease and diabetes is very mixed. Neither fussiness around new foods nor constipation are classic or very salient markers of good health. The obesity studies are debatable. The weight loss of breastfeeding mothers is taken from a WHO report, based on two interventionist studies in Honduras. It’s nothing like that straightforward: it does use 500 calories a day, but if your appetite increases at the same time, it is amazing how quickly and easily you can pop 500 calories into your mouth. Meanwhile, Wolf points out, no study on maternal cancer has “distinguished the effects of breastfeeding from the behaviour of women who breastfeed”

Again, I agree, it’s not straightforward! But I would, perhaps, strike a more positive tone.

The studies aren’t perfect (Williams also quotes the American Academy of Paediatrics: ‘There are a lot of methodological problems’), but that’s no reason to just give up on evidence altogether. The best available evidence, as far as I can see, is saying that breastfeeding is likely to bring a range of benefits to the child, and possibly some to the mother. A Cochrane Review from 2009 includes many citations that support various benefits of breastfeeding, as well as a discussion of some of the uncertainties.

I also agree that the weight loss data must be taken in context, such as whether you are dealing with developed or developing countries, and some effects, such as iron status, can be achieved through supplementation. So, in some instances, there’s no need to be over-zealous about breastfeeding, as long as adequate healthcare advice is in place.

“The notion of risk [has been] transformed from a dichotomy to a continuum.” It’s no longer a case of “safe” versus “dangerous”; rather, everything carries some risk and you announce your fitness as a parent to the world by interpreting hazards in the most credulous, fervent way. The onus isn’t on the researcher to prove the point any more – the onus is on the parent, or parent-to-be, to prove that they’ll believe the researcher.

I’m not sure this is true and seems an over-generalisation. There’s a huge variety in parental attitudes and some are incredibly questioning, and whether and how this has changed in recent years is uncertain without any data. I think it misrepresents the role of a researcher, too – that the onus is on them to ‘prove a point’. Scientists don’t (or shouldn’t) undertake work to prove already held beliefs, rather they formulate hypotheses and design experiments to support or reject those theories.

There are lots of other points in and around the ones I’ve highlighted, a lot of which veer from my intention to address evidence-based decisions, but I do encourage you to read the whole article for some interesting discussion of feminism and social policy.

I’ll summarise by saying that I would still state that breastfeeding can potentially bring a range of benefits over formula-feeding, because that is where the balance of scientific evidence is, with little or no contrary evidence to dissuade me yet. And this should be reflected in the healthcare advice that is provided. I absolutely agree, though, that foisting this decision on mothers is, at best, unnecessary and, at worst, damaging. Healthcare advice must take context into account.

On a more general point, I welcome any sensible, critical look at the evidence behind claims, as Zoe Williams has done. It’s certainly made me re-evaluate – and in some instances, such as in the link to lowered risk of maternal breast cancer, made me temper – my own standpoint on the benefits of breastfeeding.

A final point, though. It was disappointing that an article that relied so heavily on rejecting or challenging some of the evidence that is used to promote the “breast is best” standpoint, did not once link to any primary research. A few quotes here and there from, no doubt, serious academics, and a link to a book, but nothing that could point the reader to the original research studies.

It is perennial complaint that evidence-based advocates level at popular journalists, so I don’t want to single out this author for special criticism. But it is something that could do with a cultural shift and, perhaps, mainstream commentators will start to follow the examples of their science colleagues.

———————-

Hat-tip to Mum-in-law, Jenny, for The Guardian article.

On opening the door to science

I’ve been talking once again on the excellent Pod Delusion podcast, which is an audio show about all things interesting from a rational point of view. This time it was about the slightly esoteric issue of scientific publishing, that is the forum in which researchers make their findings available to the community. The issue I was discussing was whether research articles, the very channels that contain all the data and results from scientific experiments, should be freely available to whoever wants to read them (“open access”) or whether they should be allowed to be protected behind paywalls.

Some argue that if research is supported by public funds, such as that funded by the taxes all of us (or most of us!) pay, then there’s an ethical imperative that the public has a right to access the results of that research. The same goes for charity research that is funded through money raised by public donations. If one needs a subscription to read the results of the research supported by public or donated money, then that person is effectively paying twice for it.

Now bear with me. This may seem like a discussion that only those in a particular industry should care about, but it speaks of some wider concerns. These have been discussed at some length elsewhere, such as in George Monbiot’s and Stephen Curry’s excellent articles in The Guardian.

But what has all this got to do with evidence-based parenting? Well, as I mentioned briefly on the podcast, if parents really want to make evidence-based choices about everything from pregnancy to childbirth to child development, then having access to actual primary research can be invaluable. I’m not proposing that parents carry out full literature reviews to reach a conclusion on a particular issue – we rely on health professionals with appropriate expertise to provide scientifically informed advice – but there are many myths and claims into which parents may want to look a little deeper.

Myths about the validity of some alternative medicine remedies, for instance, can be quickly deflated when one looks to the proper scientific literature rather than pseudoscientific websites. Sensational claims in newspapers, which can genuinely cause undue alarm for parents, can also be tempered by actually looking at what the researchers report in a respected scientific journal. See my previous posts for examples.

The use of resources such as the Cochrane Library that hosts independent reviews of evidence for healthcare decision making, such as whether homeopathy is effective to induce labour (it’s not), is a great place to look for an overarching picture of the current state of scientific thinking. In fact, access to the Cochrane Library is opening up on a country-by-country basis, as more governments – including the UK and Ireland – negotiate ‘national provisions’ for their residents. The Cochrane Library even includes lay summaries for their articles, highlighting the desire to widen accessibility to research findings. 

I would also like to think that opening access to scientific research unveils some of the mysteries surrounding scientists and what they do. At a time when the public confidence of scientists and their work has been knocked by scandals in climate change research and human embryonic stem cells, it is incredibly important to show the inner workings of the research community. A greater access to scientific discoveries would also help to improve scientific literacy amongst the public by showcasing the scientific method. To promote the value of this work and the exciting breakthroughs it can bring should also help to maintain public support for scientific endeavour through taxes and charitable donations.

If you get the chance to talk or write to your MP, I would encourage you to ask them about open access and whether they would support a government policy to mandate this for publicly funded research. It would really help put scientifically valid evidence in the public and at the heart of decision making.

On seeking out the evidence

The running theme of this blog is trying to find the evidence behind some of the stories or claims I come across. This is often tricky, even for someone from a scientific background, as the wealth of slanted and misleading messages in the popular media is sometimes overwhelming. Part of the motivation for this blog was for my benefit in trying to separate fact from fiction, so I hope that by sharing my thoughts, it proves useful to others trying to do the same in the new and scary world of parenting.

There are many great blogs, providing informed, critical analysis of some of the health stories making the news, and I would urge anyone take a look at DiscoverNature, Scientific American, PLoS, Occam’s Typewriter and Scientific Blogging, to name a few. It’s also worth checking stories at science specialist media, such as Discover Magazine and New Scientist, which cast a more critical and cautious eye over the latest scientific research than do some popular news outlets.

As an example of the variability in journalism, see the alarmist headlines reporting the effects of high-dose radiation during pregnancy on offspring:

Frightening stuff, indeed. But the study was actually conducted on mice, which may not be a suitable model for human pregnancy, and the amount of radiation exposure wouldn’t correlate with that of a mum using a mobile phone. The Mail and The Telegraph articles actually include some of this discussion in the body text, but this is only after the sensationalist headlines that do not do the research justice. The New Scientist gave a more reasoned account, pointing out the problems with overly sensational headlines:

So, with this in mind, I wanted to highlight some sites that might be especially useful for parents in getting the facts behind the stories.

                                                    

Science Daily:

Science Daily is a dedicated science news service that provides informative and critical reporting on the latest discoveries from across all scientific disciplines, including health and medicine. The articles are balanced and accurately represent the research findings, which cuts through some of the ideological or politically motivated spin in some media.

One thing worth highlighting about Science Daily is that each article clearly cites the research on which the story is based. This allows readers to go to the source for further reading, to check the data behind the claims and find out whether there are any funding conflicts. This is often severely lacking in many newspaper articles, a deficiency that has previously attracted the ire of ‘Bad Science’ author and Guardian columnist, Dr Ben Goldacre.

Just look at Science Daily‘s reporting of the story I wrote about last month concerning on-demand vs. scheduled feeding, with a clear citation to the original research – “Feeding Your Baby On Demand ‘May Contribute to Higher IQ“. This is in contrast to the reporting of the same piece of research in many major news outlets – the Daily Mail, The Guardian, The Scotsman and Time,  which didn’t include any links to the original research.

                                                    

NHS Behind The Headlines:

This NHS-backed news service provides a critical look at the health stories in the media and teases out the evidence behind the claims. It’s a superb, unbiased resource that gets underneath the hyperbole that is often used to sell newspapers, and provides the information that really matters to people trying to make day-to-day decisions that affect their and their family’s health.

Take a look at the Daily Mail (again), which reported “Babies treated in the womb for obesity: Overweight mothers-to-be get diabetes pill to cut the risk of having a fat child”. The big splash is that obese pregnant women are being treated with the glucose-lowering drug, metformin. The aim of the trials is to reduce the chances of the children being overweight themselves, which the Mail suggests is alarming because ‘fatness’ can be solved simply by diet or exercise and because we shouldn’t be ‘drugging’ overweight but otherwise healthy mothers-to-be.

A visit to Behind The Headlines (“Baby obesity research: no need to panic”) quickly unpicks the evidence. The study is also only half-way through and will ultimately tell us whether this treatment can improve health outcomes for mother and baby. Metformin is already being used safely to help obese mothers control their blood sugar levels, which might otherwise lead to complications in pregnancy such as gestational diabetes, pre-eclampsia, premature birth, caesarean section and a larger than average baby. It may also be the case that an overweight baby is more likely to be overweight as an adult, so an early prevention is likely to be more effective than a later cure and I fail to see this as “controversial”. All of this argues against the claim that the mothers receiving the drug are ‘overweight but otherwise healthy’, given the known worse outcomes of obesity for mother and baby,

The article finishes with some general advice for women in pregnancy, such as what to do if you’re worried about losing weight before getting pregnant and whether you should alter your eating habits when pregnant.

So if you see a story in the news, especially one that may motivate you to take major health decisions, then I would suggest taking a look at Behind The Headlines.

                                                    

More or Less:

Aimed at the more statistically minded amongst us, this radio show/podcast isn’t for everyone. If, however, you enjoy some number crunching to unravel the distorted numbers and statistics used in all walks of public life, then you should find this an engaging listen. Tim Harford is a lucid and entertaining host, and handles the potentially dry subject of statistics in a competently inviting manner. Check out his Undercover Economist blog for more of his analysis.

Hear the More Or Less team discuss the figures behind the claims, Over half of new mothers who die are overweight or obese and Do mobile phone towers make people more likely to procreate?.

                                                    

These are some of sources I am aware of and which I thought might be useful to others. I’ve recently found the Parenting Science website run by biological anthropologist, Gwen Dewar, which I look forward to picking through for some more evidence-based, rational parenting information.

If anyone has other suggestions, then please share!

Demanding babies and fraught mothers

There was quite a bit of coverage at the end last week about a report published by Essex and Oxford-based researchers that looked at the effects of on-demand feeding versus scheduled feeding. The researchers analysed just over 10,000 thousand babies born in the 1990s and checked whether babies fed in a particular way at 8 weeks and 33 months achieved better academic results later in their lives and whether the well-being of the mothers was affected.

The authors of the study reported an association between being fed on-demand as a baby and higher IQ scores at 8 years and better SATs exam scores at 5, 7, 11 and 14 years. This held true for breastfed and bottle-fed babies. Another effect they uncovered was that mothers who fed on-demand reported lower confidence, higher fretfulness and worse sleep patterns.

Photo by Anton Nossik*

Now I’ve mentioned quite a few times the mantra that “correlation does not imply causation”, and so my immediate reaction to seeing this in The Guardian was ‘here we go again’. Journalists often overlook the limitations of correlative studies in favour of neat and tidy story – after all, “this behaviour causes this effect” has a bit more punch than “this behaviour is associated with this outcome, but it may be acting through a third or multiple independent variable(s)”.

For an entertaining and revealing example of this issue, I would recommend reading stand-up mathematician Matt Parker’s ‘mobile phone masts cause increase in birth rates’ hoax story.

My first thought when my wife told me about this story was that, rather than on-demand feeding directly causing the higher IQ scores, it could equally be that a third factor was at play. As a speculative example, it could be that an attentive personality primes a mother to feed on-demand and also, independently, to spend more time with their child on educational development. This is an important distinction because it would mean that mothers wouldn’t be able to improve their child’s academic chances by feeding on-demand, rather they would have to pay more attention to educational development.

The authors were well aware of possible confounders and tried to take into account other differences between the groups to narrow down the possibilities as much as possible. This involved adjusting for family income, the education level of the parents, different parenting styles, the age and sex of children, and general maternal health. After all this, there was still a significant difference – children who were fed on-demand as babies had, on average, IQ scores 4 points better than children who were fed to a schedule.

This study has an advantage over many other correlative studies in that a third group presented itself – mothers who wanted to feed to a schedule but were unable to and so fed on-demand, i.e. they wanted to be in one group (scheduled feeding) but ended up as if they were in the other group (on-demand feeding). Crucially, the children in this third group achieved the same elevated academic achievement as seen in the other on-demand group.

Photo by Tom Carmony**

This meant that the authors were able to suggest that the improved academic outcomes weren’t due to having the type of mother who wishes to feed to a schedule, but that they were due to the actual act of being fed on-demand. This relies on an assumption that the mothers in the scheduled feeding group and the attempted scheduled feeding group had similar characteristics, and would therefore have similar approaches in other ways that may affect educational development. This may not be entirely true as other, more subtle differences could exist between these groups, but it’s a tantalising result that merits further investigation. I guess measuring the amount of time spent with the child on learning and development would be something at which to look.

There will still be other factors at play and it is still essentially a correlation, but it starts to narrow down the possibilites. The authors themselves admit the limitations in their study, with the lead author Dr Maria Iacovou telling Science Daily:

“At this stage, we must be very cautious about claiming a causal link between feeding patterns and IQ. We cannot definitively say why these differences occur, although we do have a range of hypotheses. This is the first study to explore this area and more research is needed to understand the processes involved.”

Dr Iacovou was also fairly even-handed on Channel 4 news, rightly highlighting that we still don’t know the mechanism for the observed effects and this is really the first step in establishing a causal relationship.

The final thing to note about the study, is that it was gratifying that the researchers looked at both sides of the issue – the outcomes for the baby (IQ, academic achievement) and the mother (well-being indicators). I’ve written before about the importance of looking at all knock-on effects, as it can be counter-productive to focus solely on the baby if it means a serious detrimental effect on the mother’s mental health.

If on-demand feeding really does drive academic development, then implementing a healthcare strategy to encourage this must take into account the negative impact this may have on the mother and include an appropriate support mechanism. Otherwise, the effectiveness of the intervention will be limited, as mothers will be more likely to give up in favour of a reassuring routine.

As Dr Iacovou said, “mothers are people too”.

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Hat-tip to mum-in-law Jenny who sent me this story.

*CC licence: http://creativecommons.org/licenses/by/3.0/deed.en

**CC licence: http://creativecommons.org/licenses/by-nc-nd/2.0/deed.en_GB