Page last updated: May 16, 2014
Alcohol intake prior to and during pregnancy and birth outcomes

The present analysis was carried out among 1,264 women from Leeds, UK, whose alcohol intake was estimated prior to and during pregnancy.

The outcomes were birth weight of the infant and whether or not it was small for gestational age (SGA). In comparison with most previous research on this topic, this study is notable for being of a relatively small size. Further, it had a high percentage of women who consumed alcohol both prior to and during the first trimester, had a very low participation rate of eligible women (only 30%), failed to present estimated effects by ethnicity, and had some questions related to residual confounding. It is unclear how the results of this study increase our knowledge of maternal alcohol consumption and birth outcomes. Forum members do not believe that the consumption of alcohol should be recommended for pregnant women. A certain percentage of newborns will be small for gestational age, have certain deformities, and have later emotional and behavioral abnormalities. If a woman has consumed any alcohol during the pregnancy, she (and perhaps even her doctor) may blame the abnormality on alcohol consumption, whether or not it had anything to do with it. Hence, the majority of Forum members agree that women should not be encouraged to consume alcohol during pregnancy.

Further, scientific data are very consistent on the potential risks of serious adverse health outcomes of the infant from heavy maternal drinking, especially among women who are alcoholics. Heavy-drinking women who become pregnant should be strongly urged to stop their drinking.

On the other hand, sound data indicating harmful effects on the fetus of light or occasional drinking by a pregnant woman are difficult to come by. Because of the epidemiologic concerns of the present paper, described in our Forum critique, we do not believe that this study adds materially to our understanding of the topic. The serious anxiety occurring among some women who may have ingested some alcohol prior to learning that they were pregnant seems, based on numerous studies, to generally be unnecessary; the need to abort a fetus because of previous light drinking by the mother cannot be justified.

There is a serious problem in interpreting all studies of prenatal alcohol exposure and the outcomes of pregnancy because of potential confounding, especially by ethnicity, education, smoking, coexisting use of illegal drugs, etc. Further, alcohol use by pregnant women has become an especially emotional and even a moral issue, and the entangled confounders make rational analysis most difficult. This means that there is a difficult challenge for epidemiologists and statisticians, as well as for public health officials and the general public, about how to interpret results of individual research projects. The literature can support varying views, from no alcohol at all for those who might soon be expectant mothers to being able to drink moderately throughout pregnancy.

Also, it should be pointed out that the potential health benefits of moderate alcohol consumption relate primarily to middle-aged and older people, so there is no reason for pregnant women to consume alcohol for its “health effects.” Thus, it is very reasonable that the majority of women choose to avoid alcohol during pregnancy. Further, heavy drinking during pregnancy has known potentially serious consequences, and should never be encouraged. Finally, there is insufficient scientific evidence that an occasional drink of alcohol during pregnancy leads to harm to the fetus, and should not cause undue alarm in a pregnant woman who may have consumed some alcohol before she realized she was pregnant.

Reference: Nykjaer C, Alwan NA, Greenwood DC, Simpson NAB, Hay AWM, White KLM, Cade JE. Maternal alcohol intake prior to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort. J Epidemiol Community Health 2014, pre-publication. doi:10.1136/jech-2013-202934


For the full critique of this paper by members of the International Scientific Forum on Alcohol Research, please click here.
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