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Reference ranges for umbilical and middle cerebral artery pulsatility index and cerebroplacental ratio in prolonged
M Palacio1, F Figueras, L Zamora
1Institut Clínic de Ginecologia, Obstetrícia i Neonatologia, Hospital Clínic de Barcelona, Barcelona, Spain. mpalacio@clinic.ub.es
Objective:
To construct normal ranges for umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI) and cerebroplacental ratio (CPR) in prolonged pregnancies according to strict methodological criteria using polynomial regression analysis.
Methods:
This was a retrospective, cross-sectional observational study involving 140 women, 10 women for each gestational day between 287 and 300 days of gestation. Fetal Doppler parameters were assessed to construct normal reference ranges for UA PI and MCA PI. CPR was calculated as a ratio of MCA PI/UA PI.
Results:
Mathematical modeling of the data demonstrated that the optimal fit was a linear polynomial one. Mean, 5th and 95th centiles were calculated for UA, MCA and CPR and centile curves from the regression analysis were constructed.
Conclusions:
Reference ranges for UA PI, MCA PI and CPR in prolonged pregnancies have been constructed. MCA PI shows a wider range than previously reported in the literature.
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