Sixty-six pregnancies with hypertension and/or growth retardation (IUGR) were investigated (age: 23 ± 5 years; primigravidas: 30%, CS 59%; hospitalisation: 10 ± 8 days, IUGR (<10 c) 82%, intensive care 23%, fetal death 1). Umbilical (URI) and cerebral (CRI) Doppler resistance indices, and the C/U ratio (CRI/URI) were measured every 2 days from admission to delivery. HI was calculated by summing the daily%C/U reduction (in%from normal cut-off limit 1.1) over the period of observation (or mean C/U reduction in%from 1.1 × number of days of observation). Doppler C/U and HI were compared with fetal heart rate (FHR) traces, and perinatal data.
HI > 160%was associated with abnormal FHR in 80%of the cases (PPV = 87%, NPV = 88%). HI > 160%predicted the occurrence of abnormal FHR 8 ± 6 days before they happened.
A combination of intensity and duration of the fetal flow redistribution (i.e. hypoxia) evaluated by Doppler is correlated with the occurrence of abnormal fetal heart rate.