Background Foetal echocardiography has become a diagnostic method to detect foetal congenital heart disease with high probability. However, it is not only time consuming and but also difficult to visualize outflow tract of foetus early in the second trimester of pregnancy, even for an experienced obstetric ultrasonographer. Recently, many methods for screening foetal cardiac anomalies were explored, but much more work is needed to develop an effective and suitable screening method. The aim of this study was to investigate the clinical significance of utilising the ductus venosus (DV) Doppler examination and the four-chamber view of heart to screen for foetal cardiac malformation in early second trimester of pregnancy.Methods Heart and DV of 401 consecutive foetuses in early second trimester (12+1-17+6 weeks) in high risk pregnancies were examined with Acuson 128 xp/10 or Sequoia 512 ultrasound diagnostic systems. Absent or reversed flow during atrial contraction (A-wave) in the DV was defined as sufficiently abnormal to screen for foetal cardiac malformations. The foetal echocardiographic diagnosis was confirmed by postnatal echocardiography (or postmortem). The sensitivities of screening tests were compared among the three methods: DV Doppler examination, four-chamber view alone, and the combination of both techniques.Results Satisfactory examinations were obtained in 383/401 foetuses (95%). Thirty foetuses with cardiac abnormalities were confirmed by neonatal echocardiography (or postmortem). The sensitivity of DV Doppler examination or four-chamber view alone is 63 % ( 19/30) and 60 % ( 18/30), respectively. The sensitivity of combining information, DV Doppler flow waveform and four-chamber view, to screen for foetal cardiac malformation is 83% (25/30) and significantly better than that of either DV Doppler flow waveform or four chamber view alone (P<0.05).Conclusion Doppler flow waveform of DV can be used to screen for foetal cardiac malformation early in the second trimester. Combining information from Doppler flow waveform of DV and four-chamber view will improve the overall sensitivity of the screening.