Characterization of growth-restricted fetuses with breakdown of the brain-sparing effect diagnosed by spectral Doppler.

OBJECTIVE

To characterize serial findings of the middle cerebral artery (MCA) and umbilical artery (UA) flow patterns, their relationship to each other, and neonatal outcomes in growth-restricted fetuses.

METHODS

Serial pulsatility indices (PIs) from MCA and UA Doppler waveforms were measured in 41 growth-restricted fetuses until Cesarean delivery. We found three patterns, as follows: phase 1 (n = 27), UA PI < MCA PI (no brain-sparing effect); phase 2 (n = 11), UA PI > MCA PI (brain-sparing effect); phase 3 (n = 3), both PIs elevated with the absence of end-diastolic flow or presence of reverse end-diastolic flow, which was designated as the 'breakdown of the brain-sparing effect'. Umbilical cord blood gas data at delivery were compared between each group.

RESULTS

Age at delivery and body weights were significantly different for each phase. The mean body weights in all phases were significantly diminished from Japanese standard body weights, indicating growth restriction. The phase 3 pH and base excess were significantly different from those of the other two phases.

CONCLUSIONS

Growth-restricted fetuses which suffered from the state of breakdown of the brain-sparing effect were delivered early with severe growth restriction and mild metabolic acidosis. The change from decreased to increased MCA PI along with increasing UA PI may predict a severely growth-restricted infant.