Abnormal flow in the ductus venosus at weeks 11 to 13 of gestation is associated with major fetal abnormalities and fetal death, according to a report in the September issue of Obstetrics & Gynecology.
Most studies associating abnormal flow in the ductus venosus have been confined to fetuses with increased nuchal translucency thickness, the authors explain. Its relevance in fetuses with normal nuchal translucency is less clear.
Dr. Nerea Maiz and colleagues from King's College Hospital, London, UK, sought to estimate the independent contribution of abnormal flow in the ductus venosus (by Doppler) in the prediction of major fetal abnormalities and fetal death in more than 10,000 pregnancies.
Abnormal ductus venosus flow, as evidenced by a reversed a-wave on Doppler examination, was observed in 4.4 per cent of the fetuses. The prevalence of reversed a-wave was significantly higher in groups with miscarriage or fetal death (10.8 per cent), abnormal karyotype (62.1 per cent), and fetal cardiac defect (25.0 per cent) than in the normal outcome group (3.7 per cent), the investigators report.
In logistic regression analyses, reversed a-wave significantly predicted fetal death, abnormal karyotype, and fetal cardiac defect independent of other factors.
"However," the researchers caution, "in approximately 80 per cent of cases with reversed a-wave, the pregnancy outcome is normal."
Obstet Gynecol 2008;112:598-605
