[Studies on fetal middle cerebral artery blood flow velocity waveforms in the intrapartum period].
The effects of uterine contractions on fetal intracranial circulation were studied by means of two dimensional color doppler flow equipment. The Resistance Index of the Middle Cerebral Artery (MCA-RI) was evaluated and the following results were obtained. 1) The MCA-RI value during uterine contraction was significantly higher than that obtained between contractions and the highest MCA-RI value was noted during the active phase, which may mean that the descending fetal head was subjected to the strongest compression at this time. 2) A significant positive correlation was found between intrauterine pressure and the MCA-RI value at any time during labor the course of labor. 3) A significant negative correlation was noted between MCA-RI and FHR. FHR early deceleration (ED) appeared in 67% of the cases with absent end-diastolic flow velocity (AEFV), and in 100% of cases with reverse EFV. It was thus shown that intracranial hemodynamics changed dramatically in the intrapartum period even in the normal fetus.
Ueno
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Department of Obstetrics and Gynecology, Kitasato University School of Medicine, Kanagawa.
D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000196:embryology / Q000502:physiology*; D005260:Female; D006340:Heart Rate, Fetal; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D011247:Pregnancy; D014590:Uterine Contraction; D014655:Vascular Resistance