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 MCA and is used in fetal surveillance in high‑risk pregnancies and has been efficacious in antenatal fetal monitoring. Materials and Methods: Sixty‑five patients with hypertensive disorders of pregnancy and 65 normotensive pregnant controls between 20 and 39 weeks of 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 MCA Doppler velocimetric indices (peak systolic velocity [PSV], end‑diastolic velocity [EDV], (RI) Resistivity index RI‑resistivity index, pulsatility index [PI], and systolic/diastolic ratio [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 ± 9.3 cm/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 a significant statistical difference in the fetal MCA Doppler velocimetric indices between hypertensive and normotensive groups indicating that fetal MCA Doppler ultrasound is a useful tool in monitoring the hemodynamic changes in the cerebral circulation of fetuses of mothers with hypertension in pregnancy.