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Include pregnant women in studies, urge researchers

Experts say designating pregnant women as ‘vulnerable’ harms rather than protects them

Louise Prime

Tuesday, 18 July 2017

Pregnant women should not be excluded from clinical studies because this practice is unfair and potentially harmful, perpetuating the lack of knowledge about the effect of drugs in pregnancy, researchers have insisted* today in the Journal of Medical Ethics. They said the widely held principle that pregnant women are a ‘vulnerable’ group is not backed up by evidence – the only reason they are potentially vulnerable results from their exclusion from studies, meaning they are increasingly exposed to higher risks because of a lack of scientific knowledge.

The research team, from Utrecht and Amsterdam in Netherlands, pointed out that despite the need to produce evidence-based knowledge on medications for pregnant women, they remain underrepresented in clinical research; and although they are often excluded because of their supposed vulnerability, there are no universally accepted criteria for considering pregnant women as vulnerable.

They performed a conceptual and empirical analysis of vulnerability applied to pregnant women, examining 13 relevant studies to look for evidence on whether pregnant women really are vulnerable; and, if so, to what extent.

They argued that pregnant women would be classed as ‘vulnerable’ if they encountered an identifiably increased likelihood of incurring additional or greater wrong, which in this group could be linked to informed consent; susceptibility to coercion; higher exposure to risk due to lack of knowledge; or vulnerability of the foetus.

But when the researchers tested these four features against a standard definition of vulnerability, they found that pregnant women are only vulnerable because a higher exposure to risk comprises an increased wrong – and that this is caused by a lack of scientific knowledge, itself resulting from the exclusion of pregnant women from clinical research.

They said: “Our study once and for all demonstrates that there is no indication that pregnant women are vulnerable because of informed consent, susceptibility to coercion or vulnerability of the foetus. The only reason why pregnant women are potentially vulnerable in clinical research is to the extent that they are increasingly exposed to higher risks due to a lack of scientific knowledge which might render them vulnerable as research subjects.”

They called for a joint effort to promote fair inclusion by funding agencies, drug authorities, researchers, methodologists, pharmacologists, guideline committees and research ethics committees to reduce pregnant women’s vulnerability.

The authors of a linked commentary** argued that the designation of pregnant women as vulnerable “is inappropriate and disrespectful” and that rather than protecting them, it has had the opposite effect by creating a great deal of uncertainty and anxiety. They pointed out that of the 172 drugs approved by the Food and Drug Administration in the US between 2000 and 2010, nearly all (>97%) had an ‘undetermined’ risk for pregnancy. They wrote: “There is a desperate need to shift the paradigm to protect pregnant women through research, not just from research.”

They concluded: “As the world encounters new health challenges and the research enterprise responds with novel interventions to combat them, we must ensure that pregnant women are not overlooked and that they and their offspring fairly benefit from these advances in medicine. … We explicitly reject the designation of pregnant women as ‘vulnerable’.”


* van der Zande ISE, van der Graaf R, Oudijk MA, et al. Vulnerability of pregnant women in clinical research. J Med Ethics, published online first: 17 July 2017. doi:10.1136/medethics-2016-103955

** Krubiner CB, Faden RR. Pregnant women should not be categorised as a ‘vulnerable population’ in biomedical research studies: ending a vicious cycle of ‘vulnerability’. J Med Ethics, published online first: 17 July 2017. doi:10.1136/medethics-2017-104446

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