PULSATILITY INDEX IN THE FETAL ANTERIOR TIBIAL ARTERY DURING THE 2ND-HALF OF NORMAL-PREGNANCY

The objective of this prospective study was to establish reference val ues for the pulsatility index in the fetal anterior tibial artery duri ng the second half of pregnancy. Pulsed Doppler waveform analysis of 2 03 fetuses at 23-42 weeks of pregnancy was performed, each fetus being examined just once. There were neither fetal nor maternal complicatio ns detectable at the time of the examination. In the first 14 fetuses from which recordings were taken, Doppler examination was performed on both fetal legs in order to evaluate systematic differences between t he right and left legs. Intraobserver variability was analyzed by repe tition of the measurements by the same examiner in the first 130 cases . There was no difference between right and left tibial circulation. T he repeatability coefficient, defined as the 95% range for the differe nce in two repeat measurements, was 1.08. The pulsatility index of the anterior tibial artery (50th centile) increased slightly from 3.29 at 23 weeks of pregnancy to 4.09 at 42 weeks. The 5th and 95th centiles were calculated, as was the 95% confidence interval of the 5th and 95t h centiles. Examination of the fetal peripheral circulation during the second half of pregnancy is possible with a high degree of precision. Whether there are changes in peripheral arterial circulation in compr omised fetuses remains to be evaluated.