Publication Date: 2023/04/02
Abstract: The ductus venosus is a vascular shunt situated within the fetal liver parenchyma, connecting the umbilical vein to the inferior vena cava. This vessel acts as a bypass of the liver microcirculation and plays a critical role in the fetal circulation. The ductus venosus allows oxygenated and nutrient rich venous blood to flow from the placenta to the myocardium and brain. Increased impedance to flow in the fetal ductus venosus is associated with fetal aneuploidies, cardiac defects and other ad-verse pregnancy outcomes. This review serves to improve our understanding of the mechanisms that regulate the blood flow redistribution between the fetal liver circulation and fetal heart and the clinical significance of the ductus venosus waveform as generated by pressure-volume changes in the fetal heart. Materials and Methods: A cross sectional study was performed at Fetal Medicine Department, SKNMC, Pune, from August 2021 to December 2022. Total 400 women were screened at routine antenatal visit during this period, out of which 225 were selected. Fetal Doppler was performed using a Siemens Acuson X300 ultrasound machine with a 3.5 MHz convex probe. The umbilical artery, fetal middle cerebral artery and the fetal ductus venosus were sampled. The pulsatility indices were measured. Follow up of these fetuses were done and the perinatal outcome were obtained. Results: An abnormal DV was associated with an overall increased for birth by emergency caesarean (CS). Overall caesarean rate is increased for delivering babies between 28 - 32 weeks gestation irrespective of dv values possibly due to policy of caesarean section in preterm deliveries. Whereas abnormal DV values at 28 - 32 weeks, 32 - 37 weeks & 37 - 42 weeks has shown clear cut increased in caesarean section rate, NICU admission and duration of stay in NICU, intrauterine deaths, low birth weight. We have categorically identified that DV values < 5th centile and >95th centile increases perinatal morbidity & mortality. We have seen that there is substantial increase in intrauterine and neonatal deaths at < 5th centile. Conclusion: In conclusion, the DV acts as a bypass of the liver microcirculation and plays a critical role in the fetal circulation. The DV allows oxygenated and nutrient-rich venous blood to flow from the placenta to the myocardium and brain. Increased impedance to flow in the fetal DV is associated with fetal aneuploidies, cardiac defects and other adverse pregnancy outcomes. Further research is necessary to determine the importance of the DV Doppler assessment in improving perinatal outcomes.
Keywords: Fetal Hypoxemia, Diastolic Reversal, Ductus Venosus, Perinatal Outcome.
DOI: https://doi.org/10.5281/zenodo.7793035
PDF: https://ijirst.demo4.arinfotech.co/assets/upload/files/IJISRT23MAR1442.pdf
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