Assessing prevalence of alcohol consumption in early pregnancy: Self-report compared to blood biomarker analysis

Providing appropriate antenatal and postnatal care for women who drink alcohol in pregnancy is only possible if those at risk can be identified. We aimed to compare the prevalence of alcohol consumption in the first trimester of pregnancy using self-report and blood biomarker analysis. Six-hundred routine blood samples from 2014, taken at the antenatal booking appointment, in the first trimester of pregnancy, were anonymously analysed for the presence of Carbohydrate Deficient Transferrin (CDT), a validated marker of chronic alcohol exposure (normalising 2-3 weeks from abstinence) and Gamma-glutamyltransferase (GGT), a liver enzyme elevated for up to 8 weeks after alcohol exposure. In a separate sample of women, from 2015, data taken during the antenatal visit, documenting women's self-reported alcohol consumption, were collected. The percentage of women who reported alcohol intake in the first trimester was 0.8%. This compared to 74.1% of women who reported consuming alcohol before pregnancy. CDT analysis revealed a prevalence rate of 1.4% and GGT a prevalence rate of 3.5% in the first trimester of pregnancy. Although those with elevated CDT generally had high levels of GGT, only one person was positive for CDT and GGT. Results from CDT analysis and self-report may underestimate prevalence for different reasons. GGT appeared to lack specificity, but it may have value in supporting findings from CDT analysis. Further studies using additional blood biomarkers, or a combination of blood biomarkers and self-report, may be beneficial in accurately detecting alcohol drinking history in pregnancy.