OBJECTIVE: We examined the use of alcohol during early pregnancy in urban Swedish women, the ability of Swedish antenatal care to identify alcohol-related risk pregnancies and the utility of some potential tools for improving its performance. METHOD: Women attending regular antenatal care were randomized to regular assessment only (control, n = 156) or intensified screening (intervention, n = 147). In the intervention group, alcohol use was determined using the Timeline Followback (TLFB) interview, alcohol use habits with the Alcohol Use Disorder Inventory Test (AUDIT), and biomarkers for alcohol use were analyzed. Data were typically obtained in pregnancy week 12. RESULTS: In the intervention group as a whole, average absolute alcohol consumption during the first 6 weeks of pregnancy was low but highly variable (mean [SD] = 24.9 [50.5] g/week; 4.8 [6.0] episodes for the entire 6 week period); 22 women (15%) drank at levels exceeding 70 g/week during any 2 or more weeks and/or in a heavy episodic drinking pattern, 60 g/episode, on 2 or more episodes. The AUDIT had a moderate sensitivity (54%) to identify these subjects. Biomarkers identified subjects with somatic illness rather than high alcohol consumption. In the control group, only 4 (3%) were identified as using alcohol, indicating a probable underestimation of alcohol use by regular antenatal screening procedures (p = .0001). CONCLUSIONS: An unexpected proportion of pregnant women in urban Sweden consume alcohol at levels likely to produce adverse effects. Regular antenatal care did not identify most of these risk pregnancies. The TLFB identified pregnant women with risk use of alcohol during pregnancy who were only partly identified by analyzing prepregnancy alcohol use patterns with the AUDIT. Elevated laboratory markers likely indicated somatic illness rather than harmful drinking.