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Published on: May 5, 2018
Fetal breathing is associated with increased umbilical blood flow
M K Nyberg1, S L Johnsen, S Rasmussen
1Department of Clinical Medicine, University of Bergen, Bergen, Norway. miriamnyberg@gmail.com
Summary
Fetal breathing movements significantly increase umbilical blood flow by 42% during the second half of pregnancy. This suggests active regulation, impacting placental blood circulation.
Area of Science:
- Perinatology
- Fetal Physiology
- Obstetric Ultrasound
Background:
- Fetal breathing movements are known to influence umbilical blood velocities.
- The impact of fetal respiratory activity on overall placental blood flow remains unclear.
Purpose of the Study:
- To investigate whether fetal respiratory activity is associated with increased fetal blood flow through the placenta.
- To test the hypothesis that fetal breathing enhances placental circulation.
Main Methods:
- Ultrasound examinations were performed three times in 110 low-risk singleton pregnancies during the latter half of gestation.
- Fetal heart rate, umbilical artery and vein blood flow parameters were measured during both fetal rest and respiratory movements.
Main Results:
- No significant difference in mean fetal heart rate was observed between rest and breathing.
- Umbilical artery blood velocity showed no significant change, but umbilical vein cross-sectional area increased by 27% and velocity by 9% during fetal breathing.
- Mean umbilical blood flow increased by 42% during fetal breathing compared to rest.
Conclusions:
- Fetal breathing movements are associated with a substantial increase in umbilical blood flow in the second half of pregnancy.
- The observed umbilical vein distension during breathing suggests active endocrine regulation of placental blood flow.
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