Fetal left ventricular modified myocardial performance index and renal artery pulsatility index in pregnancies with isolated oligohydramnios before 37 weeks of gestation

Objective: The aim was to evaluate fetal left modified myocardial performance index (Mod-MPI) and renal artery Doppler parameters in fetuses with isolated oligohydramnios and a normal amount of amniotic fluid.
Material and Methods: This was a prospective cohort study; 25 pregnancies with isolated oligohydramnios and 25 healthy, gestational age-matched controls, between 24+0 to 36+6 weeks of gestation, were recruited. Primary outcome was to compare left modified MPI and mean fetal renal artery pulsatility index (PI). The secondary outcome was to compare adverse perinatal outcomes between the groups.
Results: Mean Mod-MPI was significantly higher (p=0.001) and isovolumetric relaxation time was longer (p=0.009) in the isolated oligohydramnios group. Mean renal artery PI values were not different between the groups. Birthweight (p=0.041) and gestational age at birth (p=0.001) were significantly lower, and incidences of delivery before 37 weeks (p=0.034) and Cesarean section due to non-reassuring fetal heart rate testing (p=0.021) were significantly higher in women with isolated oligohydramnios than the control group. We found no significant relationship between Mod-MPI and adverse perinatal outcomes.
Conclusion: Fetuses with isolated oligohydramnios have increased left Mod-MPI, which may be due to mild cardiac diastolic dysfunction. Increased Mod-MPI is not associated with adverse perinatal outcomes and does not seem to help in the management of pregnancies before 37 weeks of gestation with isolated oligohydramnios.