Association Between Alcohol Consumption and Miscarriage Predicted by Genotype

Alcohol consumption compromises health to a greater extent. Over time, excessive alcohol is the root cause for development of chronic diseases and other serious problems like liver failure, etc. 

Alcohol exposure in pregnancy is associated with miscarriage risk. Genes like ADH1C 29 encodes proteins in the alcohol dehydrogenase family and a common variant of this gene is associated with slower alcohol metabolism. Individuals who are homozygous for the variant metabolize alcohol at half the rate of individuals without the variant and therefore have prolonged exposure to circulating alcohol for similar levels of consumption.

A recent study in American Journal of Obstetrics and Gynecology aimed to understand if this difference in metabolism modified the risk between alcohol exposure and miscarriage and found that exposure to alcohol in early pregnancy is an important driver of miscarriage risk for all women and genetic propensity for fast alcohol metabolism does not confer protection against regular alcohol exposure.

Study participants reported alcohol use in the month leading up to pregnancy and through the first trimester including whether they altered alcohol use during this period, date of change, and amount consumed. In a subset of participants that provided saliva DNA samples, two common SNPs in the alcohol dehydrogenase 1 gene were genotyped using an allelic discrimination assay. Genotype was used to classify participants as fast, moderate, or slow metabolizers based on variant copy number. We used binary logistic regression to assess whether alcohol exposure during pregnancy differed by ADH1C genotype.

Among 987 participants, 52% reported alcohol exposure during pregnancy and 20% experienced a miscarriage. As indicated by genotype, 16% of women were slow metabolizers and 50% and 34% were moderate and fast metabolizers, respectively. Alcohol use during pregnancy did not differ by ADH1C genotype and it was not independently associated with risk of miscarriage. Moderate activity adjusted hazard ratio [HR] 0.75, slow activity adjusted-HR 0.78. Each additional week of alcohol use in the first trimester was associated with an increased risk of miscarriage (adjusted-HR 1.07).

Researchers concluded that there was a increased risk in miscarriage conferred by each additional week of alcohol exposure was not modified by alcohol metabolism as indicated by ADH1C genotype. Exposure to alcohol in early pregnancy is an important driver of miscarriage risk for all women and genetic propensity for fast alcohol metabolism does not confer protection against regular alcohol exposure.