Relationship of prelabor fetal cardiac function with intrapartum fetal compromise and neonatal status at term.

Objectives: To investigate prospectively the relationship of fetal cardiac function and Doppler ultrasound parameters with intrapartum fetal compromise (IFC) in appropriately grown term fetuses. Secondary aims were to correlate prenatal cardiac function with neonatal acid-base status, intrapartum fetal heart rate (FHR) abnormalities and adverse neonatal outcomes.

Methods: This was a blinded, prospective, observational, cohort study of 270 women with an uncomplicated singleton pregnancy who underwent fortnightly ultrasound assessment from 36 weeks' gestation until delivery at the Mater Mother's Hospital, Brisbane, Australia. Fetal cardiac output and blood flow parameters were assessed and correlated with intrapartum and neonatal outcomes. The primary outcome was need for operative (either Cesarean or instrumental vaginal) delivery for IFC. Secondary outcome measures were acidosis at birth, 5-min Apgar score ≤ 7, suspicious or pathological FHR abnormalities and admission to the neonatal intensive care unit.

Results: Two hundred and seventy women were included in the analysis, of whom 51 (18.9%) had an emergency operative delivery for IFC. Fetuses that had emergency delivery for IFC showed lower mean left ventricular cardiac output (LVCO) (560 ± 44 mL/min vs 617 ± 73 mL/min; P < 0.001), lower mean LVCO/right ventricular cardiac output (RVCO) ratio (0.55 ± 0.07 vs 0.64 ± 0.11; P < 0.001), lower mean cerebroplacental ratio (CPR) (1.62 ± 0.3 vs 1.90 ± 0.5; P < 0.001) and higher mean RVCO (1026 ± 105 mL/min vs 978 ± 110 mL/min; P = 0.003) compared with those that did not develop IFC. Additionally, LVCO and CPR were lower in fetuses with adverse neonatal outcome.

Conclusion: Term fetuses with estimated fetal weight > 10 centile that develop IFC have evidence of lower LVCO and higher RVCO, which are in turn associated with poorer condition of the newborn. Fetal CPR is positively correlated with LVCO. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.