If your doctor insists that you have dangerously high blood pressure during pregnancy after brandishing that dreaded cuff, it might be wise to seek a second, very experienced opinion.
A recent report in the British Medical Journal pointed up the fact that different doctors and health care workers have different ways of recording the second beat of blood pressure (the diastole), which measures when blood fills up the heart. The fuss is over whether the phase IV or phase V Korotkoff sounds accurately reflect diastolic pressure.
A similar controversy rages over the recording of diastolic blood pressure in children. (The Lancet, 20 July 1991).
This was even the subject of a heated debate at a world congress of hypertension in pregnancy in Italy last year.
This difference of opinion can present a particular problem when your blood pressure is being monitored by several people, who may have been trained differently in how to monitor blood pressure.
A recent study at St George Hospital in New South Wales found that phase IV diastolic pressure was significantly higher than that of phase V more than 10 mm Hg in 13 per cent of women.
Concluded the Australian researchers:
"It is time for detailed comparisons of direct and indirect measures of blood pressure in pregnancy and a subsequent international consensus on how to record blood pressure in pregnant women."
One reason for this disparity is the nature of the equipment, charges Prof William White, the chief of Hypertension and vascular diseases in the University of Connecticut.
White says that the cuff, called the tongue twisting "sphygmomanometer" in medicalese, is "medicine's crudest investigation."
White says he favours "ambulatory monitoring of blood pressure" using a portable electronic device strapped to the patient, which measures BP at pre set intervals over 24 hours.
This is because blood pressure can vary tremendously as much as 30 mm Hg over waking hours in a given day.