Abstract
A small ultrasonic transducer was designed and inserted into the uterus and the relation between the velocity of placental blood flow (PBF) and amniotic pressure was studied. The mean ± SD of amniotic pressure at sudden decrease of the velocity of PBF, was 42.2 ± 8.8mmHg and at recovery of the velocity of PBF, was 35.7 ± 7.4mmHg. This interval was discussed as the “loading interval” to the fetus.
For applying transcutaneous oxygen (tcPO2) electrodes to fetal monitoring, a fixing device to the fetal head was manufactured. Amniotic pressure and fetal tcPO2 were simultaneously recorded. FHR pattern was classified as no deceleration (ND), early deceleration (ED), late deceleration (LD), and variable deceleration (VD) according to the deceleration pattern, and fetal tcPO2 values were compared. LD and VD patterns showed a more hypoxic condition of fetus than did ND and ED patterns. From the relation-ship between the “loading interval” and the tcPO2 change, it was suggested that an amniotic pressure interval shorter than two minutes might cause hypoxia and at least a four-minute interval of amniotic pressure elevation should be controlled if fetal hypoxia is suggested.
