Blood-pressure measurement and classification in pregnancy

Pre-eclampsia is usually defined on the basis of new onset hypertension and albuminuria developing after 20 weeks of pregnancy. There are difficulties with measurement of these variables. Conventional sphygmomanometry remains the gold standard for blood-pressure measurement. The value of ambulatory blood-pressure measurement has yet to be established. Oedema is now omitted from all definitions of pre-eclampsia, although the finding of widespread severe oedema of sudden onset should not be ignored for clinical purposes. Definitions of pre-eclampsia based solely on hypertension and proteinuria i gnore the wide clinical variability in this syndrome. Women with no protein uria but who do have hypertension and other features such as severe headach e or other symptoms, thrombocytopenia, hyperuricaemia, disordered liver fun ction, and fetal compromise are likely to have pre-eclampsia. This notion i s accepted in the new Australasian definition of pre-eclampsia and more tha n hinted at in the new American College of Obstetricians and Gynecologists' definition. Definitions used for clinical purposes should be as safe as pr actical; they are likely to include a considerable number of false positive s. Most research studies are weakened if patients without the disease are i ncluded. Therefore, a separate stringent research definition of pre-eclamps ia we also suggest.