Timing the delivery of a compromised premature fetus is very crucial to its survival. Advances in Doppler velocimetry are encouraging and could be of valuable help during these critical times.
OBJECTIVE: This study wanted to determine if significantly more perinatal deaths and perinatal morbidities occur in fetuses with 'late' Doppler changes collectively; and to determine which of these vessel waveform abnormalities carry the greatest risk of fetal morbidity and mortality.
METHODS: This retrospective cohort included data over a 5 year period from the Women's Health Care Unit, Department of Obstetrics and Gynecology of the St. Luke's Medical Center. Doppler scans done in-utero on 30 fetuses with abnormal pulsed-wave Doppler velocimetry waveforms of the umbilical arteries, middle cerebral artery, ductus venosus and umbilical vein were reviewed; and the incidence of increased perinatal mortality and morbidity (low 1 and 5 minute APGAR scores, intubation rate and cesarean section for non-reassuring fetal status) in the presence of these abnormal waveforms were determined. Abnormal Doppler changes were categorized into 'early' (absent umbilical artery end-diastolic flow and abnormal middle cerebral artery-umbilical artery pulsatility index ratio) and 'late' (reversed umbilical artery end-diastolic flow, abnormal ductus venosus and umbilical venous pulsation).
RESULTS: 'Late' abnormal Doppler changes significantly increased the risks for low 5 minute APGAR score (RR = 8.6, p = 0.01), intubation (RR = 4.9, p = 0.03) and cesarean section for non-reassuring fetal status (RR = 2.2, p = 0.04). Most ominous was the presence of the abnormal ductus venosus waveform which greatly increased the risk for all the adverse perinatal outcomes studied: perinatal death (RR = 8.4, p = 0.03), low 1 minute APGAR score (RR = 3.4, p = 0.03), low 5 minute APGAR score (RR = 12.5, p = 0.002), intubation (RR = 4.4, p = 0.02) and cesarean section of non-reassuring fetal status (RR = 2.0, p = 0.04). A reversed umbilical artery end-diastolic flow increased the risk for perinatal death (RR-= 8.4, p = 0.03) and low 5 minute APGAR score (RR = 9.3, p = 0.02) and a pulsatile umbilical vein increased the cesarean section rate for non-reassuring fetal status (RR = 2.0, p = 0.05). None of the fetuses with only 'early' Doppler changes had low 5 minute APGAR scores nor incurred perinatal demise.
CONCLUSION: 'Late' Doppler changes increased perinatal morbidity and mortality, more specifically, the abnormal ductus venosus waveform. Fetal Doppler abnormalities reflect the severity of fetal compromise and are instrumental in the optimal timing of delivery. (Author)