Measuring blood pressure in normal and hypertensive pregnancy

The measurement of blood pressure is an integral part of antenatal care. Mercury sphygmomanometry is the gold standard for the determination of indirect blood pressure and has been used in pregnancy from the time blood pressure was first associated with adverse obstetric outcome. However, there is good evidence that current practice using mercury sphygmomanometry is far from perfect. This article will describe the history of blood pressure determination, why blood pressure is important in pregnancy and the problems associated with sphygmomanometry. It will discuss the advantages and disadvantages associated with alternative methods of blood pressure determination in pregnancy. Automated equipment should always be compared with mercury sphygmomanometry following a recognized protocol, such as that published by the British Hypertension Society, before its accuracy can be assumed in clinical practice. There is now good evidence that the accuracy of these devices deteriorates in women who develop pre-eclampsia. Home monitors have the potential to improve surveillance and to reduce in-patient monitoring.