A prospective cohort study on the prediction of fetal distress and neonatal status with arterial and venous Doppler measurements in appropriately grown term fetuses.

Purpose: To assess the predictive power of the cerebro-placental ratio (CPR) and the venous-arterial index (VAI) for the development of intrapartum fetal distress (FD) and neonatal intensive care unit (NICU) admission.

Methods: Fetal umbilical artery, middle cerebral artery and umbilical vein Doppler measurements were obtained before the active phase of labor in 311 singleton pregnancies at ≥37 weeks. A continuous electronic fetal monitorization was applied, and an umbilical cord blood sample was obtained for each participant. FD and NICU admission were the primary outcomes.

Results: Labor was concluded as uncomplicated spontaneous vaginal delivery (SVD) in 261 (83.9%) cases. The 22 (7.1%) FD cases were subdivided into FD with NICU admission (n: 7; 2.3%) and without NICU admission (n: 15; 4.8%). Six out of 7 (85.8%) FD with NICU admission cases were from nulliparous pregnancies. The combinatory indices (VAI and CPR) reached the highest sensitivity (31.8%) and negative predictive value (94.7%). None of the fetuses, distressed or non-distressed, with CPR ≤ 10th percentile was born with a cord pH < 7.20.

Conclusion: FD frequency was increased in fetuses with a low CPR or low VAI. However, the Doppler patterns were heterogeneous in both subgroups: FD with and without NICU admission. FD seems to be a common endpoint of different circulatory-metabolic disturbances. Parity affects the FD frequency in a manner related but not limited to fetal arterial and venous circulation. Low CPR could be a part of the adaptive mechanisms providing metabolic preparedness for hypoxic episodes.