Umbilical artery PI and fetal movements/hour as predictors of neonatal acidemia in high risk pregnancies

Objective: The aim of this study was to correlate antepartum computerized c ardiotocography (cCTG) and Doppler velocimetry parameters to umbilical bloo d gas analysis (UBGA) value and Apgar score 1-5 min as neonatal outcome end points. Methods: Fourty-eight third trimester single high risk pregnancies were con sidered for this study, with a cCTG performed within 24 hrs from delivery, a complete Doppler velocimetry study performed within 48 hrs from delivery and an UBGA evaluation at birth and before the first breath. Results: When we analyzed the backward stepwise regression of each Doppler velocimetry and cCTG parameters versus UBGA parameters as dependent variabl es, we found that the a linear combination of FHR (p< 0.001), HV min (p<0.0 1) and LV msec (p<0.03) was able to predict pO(2) values. When performing a logistic regression of data for every single parameter of FHR tracing and Doppler velocimetry against pH<7.2 and Becf<-4 as endpoints, we found that only UA PI was able to predict UA pH (O.R.: 8.1 [1.07-61.8]) and only FM fr om FHR tracing values was able to predict UA pH (O.R.: 0.94 [0.89-0.99]). F urther analysis considers a cut-off for the prediction of UA pH<7.2 at birt h a value at greater than or equal to1.35 for UA PI and at less than or equ al to 12 for FM/h. The combination of UA PI > 1.35 and FM/h <12 did not imp rove the ability to predict acidemia at birth. Conclusion: The validity of our data from the clinical point of view sugges ts that in third trimester high risk pregnancies, an UA PI<greater than or equal to>1.35 and/or FM/h less than or equal to 12 (in a FHR tracing greate r than or equal to 40 min) may represent a risk of 70% acidemia in neonates .