Multivascular Doppler surveillance in high risk pregnancies.

OBJECTIVES: Analysis of fetal arterial and venous Doppler predictability for adverse perinatal outcome. METHODS: Blood flow in the uterine, umbilical and middle cerebral arteries, umbilical vein, ductus venosus and Galen vein were examined with in 72 h of delivery in 88 high-risk pregnancies. The managing clinicians were only informed about the results of the umbilical artery Doppler. The Doppler results were correlated to adverse perinatal outcome. RESULTS: Doppler abnormalities were seen in both preterm and term pregnancies. Umbilical venous pulsations (n = 13) were strongly correlated to Apgar score <7 at 5 min, abnormal blood gases, need for ventilation assistance and operative delivery for fetal distress. Twenty-four fetuses had brain sparing in the middle cerebral artery, and forty-five had abnormal umbilical artery Doppler. These were correlated to admission in the neonatal intensive care unit, operative delivery and prematurity. Brain sparing in middle cerebral artery was also correlated to ventilation disturbances in the newborns. Abnormal ductus venosus blood velocity was only seen in 9 cases and not related to adverse outcome. Galen vein pulsations (n = 26) seem to appear earlier than pulsations in the umbilical vein and were not related to adverse outcome. conclusion: Umbilical vein pulsations were better correlated to adverse perinatal outcome than were other Doppler findings including ductus venosus.

Signs of fetal brain sparing are not related to umbilical cord blood gases at birth.

BACKGROUND: Fetal chronic hypoxia leads to centralization of circulation in order to spare the vital organs brain, adrenals and the heart. This can be documented by Doppler ultrasound. Increased blood velocity in the fetal middle cerebral artery (MCA) is an acknowledged sign of centralization of circulation in chronic hypoxia, and is called brain sparing. AIM: Our aim was to assess the relationship between signs of brain sparing in the MCA and umbilical cord blood gases at birth. STUDY DESIGN: A prospective study. SUBJECTS: Singleton 57 high-risk pregnancies (outcome was compared with 21 normal pregnancies). METHODS: MCA Doppler was performed within 24 h of elective caesarean section in high-risk pregnancies. Umbilical cord blood gases were analysed at birth. MAIN OUTCOME MEASURES: Cord blood gases were related to signs of centralization of fetal circulation in the MCA. RESULTS: No correlation between signs of brain sparing in the MCA and cord blood gases. Apgar score at 5'<7 was seen in three newborns, but only one of these had antenatal signs of brain sparing. Newborns with antenatal brain sparing were admitted more often (p<0.04) and had a longer duration of stay in NICU (p<0.03) compared to newborns without brain sparing. CONCLUSION: Decreased pulsatility index in MCA is an acknowledged sign of fetal centralization of circulation during chronic hypoxia. However, signs of brain sparing are not related to cord blood gases at birth, which might suggest that redistribution of fetal circulation can maintain normal blood gases for a long time during chronic hypoxia.

Fetal brain sparing is strongly related to the degree of increased placental vascular impedance.

BACKGROUND: Doppler ultrasound examination has become an established method of clinical surveillance in high-risk pregnancies. Doppler indication of fetal brain sparing (BS) is an acknowledged sign of circulation redistribution during chronic hypoxia. OBJECTIVES: To evaluate the relationship between placental vascular resistance and signs of BS in middle cerebral artery (MCA) blood flow velocity. METHODS: The MCA, uterine artery, and umbilical artery (UA) were located by color Doppler ultrasound in 103 high-risk pregnancies at risk for intrauterine fetal hypoxia. The blood velocity spectrum was analyzed for the following parameters: pulsatility index (PI) and signs of notching in the uterine arteries. Z-score was calculated for the MCA PI. RESULTS: Signs of BS in the MCA were correlated to increased placental vascular impedance. The degree of BS in the MCA expressed as Z-scores was correlated to increasing vascular impedance, both in the umbilical and uterine arteries, and to adverse outcome of pregnancy. The greatest deviation in MCA PI Z-scores was seen in preterm pregnancies. CONCLUSION: A clear correlation exists between increasing placental vascular impedance and BS in the MCA. Preterm pregnancies express the greatest deviation from the mean MCA PI.