OBJECTIVE: Ductus venosus and inferior vena cava flow velocity was assessed in fetuses in isoimmunized pregnancies. METHODS: Examination of 61 fetuses aged 27 to 35 weeks from Rh-erythrocyte antigen isoimmunized women was carried out from June 1999 to June 2004. All fetuses were submitted to the examination of ductus venosus and inferior vena cava flow velocity. Blood samples were collected to determine hemoglobin values and hemoglobin concentration deficits. Accordingly, fetuses were grouped as follows: non-anemic; mildly anemic; moderately anemic and severely anemic fetuses. Comparison of the variation of average flow velocity in the inferior vena cava and ductus venosus across the four groups was carried out using the chi-square test. RESULTS: Inferior vena cava flow velocity was found to be altered in 3.8% of non-anemic fetuses; in 3.1% of the mildly anemic, in 40.0% of those moderately anemic; and in 76.0% of the severely anemic ones. Alteration in ductus venosus flow velocity, in turn, was identified in 7.7% of non-anemic fetuses; 3.1% of mildly anemic; 32.5% of moderately anemic and 68.0% of those severely anemic. Results were statistically significant with p < 0.001. CONCLUSION: The study shows that alteration of flow velocity in the inferior vena cava and ductus venosus increased with the severity of anemia.
Isoimmunization; Fetal anemia; Doppler flowmetry; Inferior vena cava; Ductus venosus
