FMF Certification
Ductus venosus flow
Increased impedance to flow in the fetal ductus venosus at 11-13 weeks’ gestation, is associated fetal aneuploidies, cardiac defects and other adverse pregnancy outcomes. Most studies examining ductus venosus flow have classified the waveforms as normal, when the a-wave observed during atrial contraction is positive, or abnormal, when the a-wave is absent or reversed. The preferred alternative in the estimation of patient-specific risks for pregnancy complications is measurement of the pulsatility index for veins (PIV) as a continuous variable.
Inclusion of ductus venosus blood flow in first-trimester combined screening improves the detection rate for trisomy 21 from about 90% to 95% for a false positive rate of 3%. Assessment of ductus venosus flow need not be carried out in all pregnancies undergoing routine first-trimester combined screening. Such examination could be reserved for the 15% of the total population with an intermediate risk (between 1 in 51 and 1 in 1000) after combined testing.
Requirements for certification
Attendance of the internet based course on the 11-13 weeks scan (link under Education - the 11-13 week scan log in). We are no longer accepting images for assessment. Our new FMF website will launch in December 2025, where you will be required to complete the Cervical Assessment and Preeclampsia Screening online courses.
Protocol for images
- The gestational period must be 11 to 13 weeks and six days.
- The examination should be undertaken during fetal quiescence.
- The magnification of the image should be such that the fetal thorax and abdomen occupy the whole image.
- A right ventral mid-sagittal view of the fetal trunk should be obtained and color flow mapping should be undertaken to demonstrate the umbilical vein, ductus venosus and fetal heart.
- The pulsed Doppler sample volume should be small (0.5-1.0 mm) to avoid contamination from the adjacent veins, and it should be placed in the yellowish aliasing area.
- The insonation angle should be less than 30 degrees.
- The filter should be set at a low frequency (50-70 Hz) so that the a-wave is not obscured.
- The sweep speed should be high (2-3 cm/s) so that the waveforms are spread allowing better assessment of the a-wave.
- When these criteria are satisfied, it is possible to assess the a-wave and determine qualitatively whether the flow is positive, absent or reversed.
- The ductus venosus PIV is measured by the machine after manual tracing of the outline of the waveform.
Color Doppler of Ductus venosus
Positive a-wave
Reversed a-wave
