Fetal doppler velocimetry of the middle cerebral artery in hypertensive disorders of pregnancy, in Kano, Nigeria

Background: Hypertension is one of the leading causes of maternal and fetal mortality and morbidity. The middle cerebral artery (MCA) is the major supplier of blood to the brain. Doppler velocimetry has made it possible to identify and insonate the fetal middle cerebral artery and is used in fetal surveillance in high-risk pregnancies and has been efficacious in antenatal fetal monitoring. Methods: Sixty-five patients with hypertensive disorders of pregnancy and sixty-five normotensive pregnant controls between 20 and 39weeks gestational age were recruited for this study. Obstetric ultrasound scan was done to determine the gestational age, estimated fetal weight and amniotic fluid indices. Fetal middle cerebral artery Doppler velocimetric indices (PSV, EDV, RI, PI and S/D ratio) were also measured and documented. Results: The mean PSV of the study group (32.1±10.1 cm/s) was lower than that of the control group (38.6±9.3cm/s). This difference was not statistically significant (p=0.416). However, the mean EDV of the study group (9.09±2.9 cm/s) was higher than that of the control group (8.6±2.0 cm/s) which was also not statistically significant (p=0.074). There was a statistically significant difference (p=<0.001) between the mean RI of the study group (0.70±0.10) and that of the control group (0.77±0.05). The mean PI of the study group (1.35±0.5) was also lower than that of the control group (1.49±0.3), which was statistically significant (p=<0.001). There was also a statistically significant difference (p=0.003) between the mean S/D ratio of the study group (3.64±1.4) and that of the control group (4.5±1.1). Conclusion: There was significant statistical difference in the fetal middle cerebral artery Doppler velocimetric indices between hypertensive and normotensive groups indicating that Fetal middle cerebral artery Doppler ultrasound is a useful tool in monitoring the haemodynamic changes in the cerebral circulation of fetuses of mothers with hypertension in pregnancy.