The effect of nifedipine and methyldopa on maternal cerebral circulation.
OBJECTIVE
To study how the treatment of severe gestational hypertension affects maternal middle cerebral artery velocimetry.


METHODS
Prospective, clinical, descriptive study.


METHODS
John Radcliffe Maternity Hospital, Oxford, England.


METHODS
Pregnant and puerperal women who required acute or chronic antihypertensive treatment with nifedipine (n = 46) or methyldopa (n = 26), respectively.


METHODS
Transcranial Doppler ultrasound examinations of maternal middle cerebral arteries were performed before and 45 min after nifedipine; and before and 48 hours after the onset of methyldopa therapy. Blood pressure and heart rate were also recorded.


METHODS
Clinical and transcranial Doppler changes induced by the antihypertensive medication.


RESULTS
Blood pressure and middle cerebral artery velocities decreased significantly following both short- and long-acting antihypertensive therapy. Nifedipine-induced changes were more pronounced and uniform than those found after methyldopa (16.7% and 6.4% decrease in middle cerebral artery mean velocity, respectively). The middle cerebral artery mean velocity decrease was independent of changes in the blood pressure or heart rate.


CONCLUSIONS
Maternal cerebral haemodynamics are influenced by antihypertensive treatment. The reduction of middle cerebral artery flow velocities following administration of nifedipine and methyldopa may suggest that cerebral vasodilatation is occurring, which is consistent with the concept that cerebral vasospasm is present in women with pre-eclampsia. The cerebral vasodilatation could result from a direct effect of the medication on the arteries in question.
Serra-Serra
V
V
University of Oxford, Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Maternity Hospital.
Kyle
P M
PM
Chandran
R
R
Redman
C W
CW
D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D002536:Cerebral Arteries / Q000187:drug effects / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008750:Methyldopa / Q000627:therapeutic use*; D009543:Nifedipine / Q000627:therapeutic use*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy / Q000503:physiopathology*; D011446:Prospective Studies; D018084:Ultrasonography, Interventional; D014665:Vasodilator Agents / Q000627:therapeutic use*
D000959:Antihypertensive Agents; D014665:Vasodilator Agents; D008750:Methyldopa; D009543:Nifedipine