Epigenetics, media, and worrying pregnant women

fetusDon’t do this. Don’t do that. Eat this. Eat that.
No, I’m not ordering a kid about. Just telling a pregnant woman how she should behave.

No one is denying that a healthy lifestyle is important during pregnancy, but it sometimes feel as if too much emphasis is placed on a woman’s individual influence on her future baby’s health. In a comment published in Nature this week, Sarah Richardson, associate professor at Harvard University, and colleagues express their concern about how “careless discussions of epigenetic research on how early life affects health across generations could harm women”.

Holding women responsible for whatever “defect” afflicts the child they deliver is not new, and there was a time, when not much was known about human reproduction, health and disease, when it probably made intuitive sense. As Richardson notes, until the 19th century, most of the medical community thought that birth defects were caused by the mother’s diet, “nerves” (whatever that meant), or even “the company she kept during pregnancy”.

As scientific and medical knowledge progressed, useful discoveries were made that allowed for a better understanding of the cause of certain birth defects, and importantly, for adequate recommendations to prevent these birth defects. For example, folic acid deficiency in early pregnancy has been linked to the risk of spina bifida, a neural tube defect, and women are now advised to ensure that their diet contains enough folic acid and/or to take dietary supplements when they consider a pregnancy (note: the exact causes of spina bifida are still unknown, and it is thought to result from a combination of genetic and environmental factors). Another example is the recognition in the 1970s that heavy alcohol consumption during pregnancy causes fetal alcohol syndrome, a collection of mental and physical problems in the child.

However, the authors of the Nature comment also use the case of alcohol consumption to suggest that scientific findings may sometimes be too much extrapolated and lead to over-reach and over-regulation. In the US, the general policy is that no level of alcohol consumption is safe during pregnancy, and you cannot walk into a bar or a restaurant without seeing the sign that reminds you so. Having even just a sip of wine is highly stigmatized and most women stop drinking altogether. Yet, Richardson and colleagues cite a study done in Denmark that did not find adverse effects in children of mothers who drank moderately during pregnancy.

The main focus of Richardson and colleagues in their Nature article is how the results of epigenetics research are discussed in society at large, and how bad press reporting and over-hyping/over-extrapolating of preliminary data may put too much emphasis on a woman’s individual behavior and its influence on her future child’s health. (Epigenetics refers to DNA modifications that affect the activity of a gene without changing its nucleotide sequence. In the past few years, there has been a wave of studies seeking to understand if epigenetic changes could be passed on from parents to offspring and if parents’ lifestyles, environmental exposures and life experiences could affect the development and health of their offspring.)

The authors of the Nature article express their concern at the risk of over-emphasizing the mother’s individual influence on her child’s future health, to the detriment of other factors such as the influence of the father or that of social and environmental factors. They give examples of headlines in the press that put the whole focus on the mother: “Mother’s diet during pregnancy alters baby’s DNA”, “Why you should worry about grandma’s eating habits”. As often in science reporting, the relative lack of context, oversimplification and absence of discussion of the other factors involved and of the limitations of the study make for catchy and easy stories, but stories that misrepresent the real significance of the original scientific results. At the same time, such headlines and stories may just serve to create stress and guilt in pregnant women whose behavior is increasingly being put under scrutiny and regulated.

Richardson and colleagues end their comment by making a few recommendations to scientists, journalists and educators alike (recommandations that are also worth keeping in mind for anyone):

– don’t extrapolate results from animal studies to humans without substantial reasons to do so
– don’t just emphasize maternal impact, also discuss the influence of other factors, such as paternal impact, socioeconomic status, environmental stressors, etc.
– convey complexity: intrauterine exposures may affect the child’s future health, but so too can many other factors, and their individual and combined impacts are difficult to evaluate and understand
– recognize the role of society, don’t single out women: Richardson and colleagues note that many of the intrauterine stressors identified as having intergenerational effects correlate with social gradients of class, race, and gender, which, they suggest, highlights “the need for societal changes rather than individual solutions”.

A generation ago, pregnant women did not have access to the plethora of information that their daughters can nowadays find online. So they listened to their physician for health recommendations. Having access to more information is generally a good thing, but I’m not sure having headlines scaring women into worrying about every single aspect of their behavior during pregnancy is.

Reference
Society: don’t blame the mothers. Richardson SS, Daniels CR, Gillman MW, Golden J, Kukla R, Kuzawa C, Rich-Edwards J. Nature. 2014 Aug 13;512(7513):131-2. doi: 10.1038/512131a

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