Prelabour myocardial deformation and cardiac output in fetuses that develop intrapartum compromise at term: a prospective observational study.

Objective: Redistribution of cardiac output is responsible for the "brain sparing" effect seen during periods of acute or chronic fetal stress. We investigated the relationship between prelabour cardiac function in fetuses that subsequently developed intrapartum fetal compromise (IFC). Methods: A blinded, prospective, observational, cohort study, at Mater Mother's Hospital, Brisbane, Australia. A cohort of 284 women with uncomplicated singleton pregnancies underwent ultrasound every 2 weeks from 36 weeks until delivery. Fetal cardiac output was assessed by conventional Doppler ultrasound and myocardial deformation was measured using velocity vector imaging. Results: Two hundred and seventy three women were included in the final analysis, of which 19% had an emergency operative delivery for intrapartum fetal compromise (IFC). Global left ventricular strain (-12.1%, interquartile ranges (IQR) - 10.3 to -14% versus 13%, IQR -11.3 to -14.2%, p = .01) and strain rate (-1.00, IQR 0.85-1.16 s-1 versus -1.11, IQR -1.00 to -1.21 s-1, p < .001) were lower in fetuses that required any emergency operative delivery for IFC compared to those that did not. Global longitudinal right ventricular strain rate was lower in fetuses that developed IFC (-1.04 ± 0.22 s-1 versus 1.13 ± 0.22 s-1, p < .001), whereas global right ventricular strain did not show any significance differences between the two groups. Additionally, left ventricular cardiac output was lower in fetuses that developed IFC or had a composite neonatal morbidity (560 ± 44 mL/min versus 617 ± 72 mL/min, p < .001) or (581 ± 44 mL/min versus 612 ± 72 mL/min, p < .01), respectively. Conclusion: Lower global left ventricular strain and strain rate and cardiac output are associated with IFC and poorer condition of the newborn. Assessment of fetal cardiac function may be useful for risk stratification for intrapartum fetal compromise in apparently "low risk" term pregnancies.

Assessment of left ventricular function using the Myocardial Performance Index in term fetuses that develop intrapartum compromise.

OBJECTIVE: To investigate the relationship between the prelabour left ventricular Myocardial Performance Index (LVMPI) and intrapartum fetal compromise (IFC) in low-risk term pregnancies. METHODS: A blinded, prospective observational cohort study at the Mater Mother's Hospital, Brisbane, Australia. A cohort of 284 women with uncomplicated singleton pregnancies underwent fortnightly ultrasound from 36 weeks until delivery. The LVMPI was assessed by conventional Doppler ultrasound and correlated with intrapartum outcomes. The LVMPI was also correlated with other Doppler indices of fetal wellbeing. RESULTS: Two hundred and seventy-three women were included in the final analysis, the median LVMPI was higher in fetuses that required any emergency operative delivery for IFC (0.56, 0.52-0.60 versus 0.54, 0.50-0.58, p = .007). The left ventricular cardiac output (LVCO) and cerebroplacental ratio (CPR) were lower in fetuses that required any emergency operative delivery for IFC compared to those that did not (164 ± 19 ml/min/kg versus 181 ± 30 ml/min/kg, p < .001) (1.63 + 0.30 versus 1.90 + 0.50, p < .001), respectively. The LVMPI was inversely correlated with the CPR (r = -0.20, p < .01), MCA PI (r = -0.29, p < .01), and LVCO (r = -0.22, p < .01). CONCLUSIONS: Higher global LVMPI is associated with a higher risk for IFC and poorer condition of the newborn.