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Should women abstain from alcohol throughout pregnancy?

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h5232 (Published 06 October 2015) Cite this as: BMJ 2015;351:h5232

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Re: Should women abstain from alcohol throughout pregnancy?

While the teratogenicity of alcohol has been well established, evidence of harm attributable to low-level prenatal alcohol exposure is less clear.

Some early human and animal observational studies among small samples report a dose-dependent effect of prenatal alcohol exposure on IQ. Many more recent studies using rigorous methodologies, however, have found an inverted J-shaped relationship between alcohol exposure and IQ. That is, children exposed to low levels of alcohol show higher IQ scores than children not exposed to any alcohol, and those exposed to higher amounts. Large-scale prospective longitudinal studies including the Avon Longitudinal Study of Parents and Children and the Millennium Cohort study have shown this pattern.

Contrary to what has been reported by Mary Mather and Kate Wiles in this article, the 2014 meta-analysis referred to actually did not show any adverse effects of low level alcohol exposure on childhood behaviour cognition. In fact, a small yet significant ‘positive’ effect of low-level prenatal alcohol exposure was apparent, corroborating findings of the aforementioned cohort studies. However, this finding was no longer statistically significant when only studies controlling for socio-economic factors were included. Nonetheless, to conclude that there is evidence of harm associated with consumption of as little as two glasses of wine during pregnancy would be misrepresenting the best available evidence on the subject.

The premise of the argument in favour of promoting abstinence put forward here, and which forms the basis of public health guidelines advising abstinence, is that there is no evidence for a “safe” threshold of consumption. This is true, and this precautionary principle can be sensibly argued, particularly where the goal is prevention of FASD. In turn, however, there is also no evidence for an “unsafe” threshold of consumption, and this too should be acknowledged. Threat-based messages have been criticised for framing the problem of alcohol use in pregnancy in ways that marginalise the needs of women, particularly those with severe alcohol-related problems. Consideration of the needs of women with an alcohol use disorder who fall pregnant has remarkably often been omitted from discourse regarding alcohol use during pregnancy.

Ensuring that public health messages are consistent with empirical research is an ethical imperative that demonstrates respect for the autonomy of women, and their capacity to make informed choices about behaviour. Maintaining a clear stance advising abstinence from alcohol during pregnancy as the “safest option” in order to reduce the risk of FASD is important. However, without acknowledging that little evidence exists linking low-level prenatal alcohol exposure with actual harms, such messages are likely to be met with scepticism, and perceived to be sensationalised and paternalistic, potentially diminishing their efficacy.

References:

Alati, R., Davey Smith, G., Lewis, S. J., Sayal, K., Draper, E. S., Golding, J., . . . Gray, R. (2013). Effect of prenatal alcohol exposure on childhood academic outcomes: Contrasting maternal and paternal associations in the ALSPAC study. PLoS One, 8(10), e74844.

Alati, R., Macleod, J., Hickman, M., Sayal, K., May, M., Smith, G. D., & Lawlor, D. A. (2008). Intrauterine exposure to alcohol and tobacco use and childhood IQ: Findings from a parental-offspring comparison within the Avon Longitudinal Study of Parents and Children. Pediatric Research, 64(6), 659-666.

Flak, A. L., Su, S., Bertrand, J., Denny, C. H., Kesmodel, U. S., & Cogswell, M. E. (2014). The association of mild, moderate, and binge prenatal alcohol exposure and child neuropsychological outcomes: a meta-analysis. Alcoholism: Clinical and Experimental Research, 38(1), 214-226.

Kelly, Y., Iacovou, M., Quigley, M., Gray, R., Wolke, D., Kelly, J., & Sacker, A. (2013). Light drinking versus abstinence in pregnancy–behavioural and cognitive outcomes in 7‐year‐old children: a longitudinal cohort study. BJOG: An International Journal of Obstetrics & Gynaecology, 120(11), 1340-1347.

Kelly, Y. J., Sacker, A., Gray, R., Kelly, J., Wolke, D., Head, J., & Quigley, M. A. (2012). Light drinking during pregnancy: still no increased risk for socioemotional difficulties or cognitive deficits at 5 years of age? Journal of Epidemiology and Community Health, 66(1), 41-48.

Kelly, Y., Sacker, A., Gray, R., Kelly, J., Wolke, D., & Quigley, M. A. (2009). Light drinking in pregnancy, a risk for behavioural problems and cognitive deficits at 3 years of age? International Journal of Epidemiology, 38(1), 129-140.

Competing interests: No competing interests

12 October 2015
Clare A McCormack
Research Officer
National Drug and Alcohol Research Centre, University of New South Wales
NDARC, The University of New South Wales, UNSW Sydney, NSW, Australia 2010