PURPOSE: to evaluate the relationship between S/A ratio in ductus venosus (DV) and perinatal outcomes in fetuses with brain sparing reflex. METHODS: the study was designed as an observational, sectional study with prospectively collected data. Forty-one fetuses with brain sparing reflex and gestational age between 25 and 33 weeks were studied between November 2002 and July 2005. The newborns were observed during the neonatal period in the intensive care unit of "Clínica Perinatal Laranjeiras" in order to find adverse outcomes. The study population was divided into two groups according to DV assessment. In the normal group all the fetuses with S/A ratio values of 3.6 or less were included, and in the abnormal group the fetuses with values of S/A ratio greater than 3.6. The statistical analysis was performed by the Mann-Whitney U-test, chi2 test and Fisher exact test. The results were considered significant when p<0.05. Gestational age, birth weight and Apgar score less than 7 at 5 min were evaluated. Perinatal outcome parameters were: intrauterine death, neonatal mortality, seizures, intraventricular hemorrhage, leukomalacia, need of surfactant, mechanical ventilation, myocardical failure, necrotizing enterocolitis, and length of stay in the intensive care unit. RESULTS: among the assessed 41 fetuses, 26 (63.4%) showed normal DV S/A ratio and the other 15 (36.6%) developed an abnormal DV S/A ratio (>3.6). There was no statistically signicant difference between the groups according to gestational age at delivery and Apgar <7. The only significant association was between abnormal DV S/A ratio and neonatal death (p=0.049; Fisher's exact test). No statistically significant association was observed for the other studied variables. CONCLUSIONS: our results suggest that abnormal DV blood flow detected by Doppler examination is not associated with adverse perinatal outcomes, except for neonatal mortality. This association may be considered statistically borderline (p=0.049). Excluding fetuses with birth weight less than 400 g, there was no other association between DV and neonatal mortality. The abnormal DV S/A ratio was not associated, in our study, with perinatal mortality in viable preterm fetuses.
Laser-doppler flowmetry; Fetal blood; Fetal distress
