Prenatal substance use in Slovenia: first national study using self-reported data and biomarkers

Alcohol, tobacco, and cannabis use during pregnancy pose significant risks to foetal and child health. National data for Slovenia are limited, particularly those integrating self-reported and objective measures of prenatal exposure. The objective of the study was to estimate the prevalence of alcohol, tobacco, and cannabis use among pregnant women in Slovenia using self-reported data and meconium biomarkers for alcohol and cannabis. A cross-sectional national study was conducted across all 14 Slovenian maternity hospitals. Sample size was based on population size, annual births, and European prevalence estimates, ensuring population-level representativeness. Postpartum women completed an anonymous questionnaire on substance use during pregnancy. In parallel, meconium samples were randomly and anonymously collected to reduce selection bias. Samples were analysed using liquid chromatography–tandem mass spectrometry for alcohol (EtG, (EtS), and cannabis metabolites (THC-COOH, THC-OH, THC). However, biomarkers in meconium reflect mainly third-trimester exposure and do not reliably capture early pregnancy exposure. Questionnaire and biomarker data were not linked. A total of 744 questionnaires and 651 meconium samples were analysed. Self-reported tobacco use was 30.6% before pregnancy, 9% in the first trimester, and 5% thereafter. Alcohol use was reported by 43%, 6.7%, and ∼3%, respectively. Cannabis use was reported by 14.3%, 3.8%, and 0.8%, respectively. Meconium analysis detected EtG in 6.1% of samples (8.7% including borderline values), while cannabis exposure was identified in 0.95%. This first national Slovenian study indicates lower prenatal alcohol and cannabis exposure than European estimates, while tobacco use is consistent with WHO regional data. By combining self-reported and biomarker data, this study fills an important gap in the epidemiological understanding of prenatal substance use and offers evidence to support targeted public health interventions.

Key messages

• Biomarkers combined with self-reported data provide a more comprehensive and robust assessment of prenatal substance use, improving the accuracy of public health surveillance.

• Targeted public health interventions are needed to address usually under-detected alcohol and cannabis use during pregnancy.