Even Limited Alcohol Use in the First Trimester Has Adverse Effects

March 14, 2014

Maybe that one glass of wine isn’t so harmless. New research suggests that even small amounts of alcohol in the first trimester can increase the risk of adverse outcomes.

Drinking alcohol before pregnancy and during the first trimester was associated with an increased risk of premature birth or having an unexpectedly small baby, according to research published online in the Journal of Epidemiology and Community Health.

Researchers found a two-fold increase in the odds of babies being small for gestational age when born to mothers who drank more than 2 units of alcohol a week compared with nondrinkers. 

Pertinent Points

- Drinking alcohol during the first trimester was associated with an increased risk of premature birth or having a small-for-gestational-age baby.

- Pregnant women and women planning to become pregnant should be advised to abstain from drinking alcohol.

The British study revealed that nearly two thirds of women before pregnancy and over half of women in the first trimester reported alcohol intakes above the United Kingdom’s Department of Health guidelines of 2 units or less per week. Even women who followed the guidelines but who did not abstain from alcohol consumption during the first trimester were at significantly higher risk for having preterm birth and for having babies with a lower birth weight and a lower birth percentile, the authors reported.

“Our findings suggest that women should be advised to abstain from alcohol when planning to conceive and throughout pregnancy,” the authors concluded.

The association with adverse birth outcomes was strongest with alcohol consumption in the first trimester. The prevalence of imbibing in more than two drinks a week was highest before pregnancy (74%) and in the first trimester (53%), with mean intakes for women reaching 15.1 units (95% CI, 14.1 to 16.1) and 7.2 units (95% CI, 6.6 to 7.9) per week, respectively.

The research was based on responses to food frequency questionnaires from 1,264 women at low risk for birth complications participating in the Caffeine and Reproductive Health study. The women were asked how often they drank alcohol, and what type it was, at four time points: the four weeks before conception and each of the subsequent trimesters.

Those who exceeded the government recommendations were more likely to be older, educated, of white ethnicity, and to live in affluent areas.

References:

Nykjaer C, Alwan NA, Greenwood DC, et al. Maternal alcohol intake prior to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort. J Epidemiol Community Health. 2014;doi:10.1136/jech-2013-202934.