The definition of pre‐eclampsia

Abstract

Background Redman and Jefferies have proposed a revised definition of pre-eclampsia which is based on absolute blood pressure levels and an increment from the baseline in the first half of pregnancy. There is no requirement for proteinuria. This definition should facilitate the distinction between nonproteinuric pre-eclampsia and other causes of nonproteinuric gestational hypertension, such as chronic essential hypertension. Objectives 1. To determine whether the blood pressure criteria of Redman and Jefferies can select women with characteristics of pre-eclampsia from the group of women with gestational hypertension by the current criteria of the International Society for the Study of Hypertension in Pregnancy (ISSHP). 2. To determine the level of agreement between the classification system proposed by Redman and Jefferies and that of the ISSHP. Design A prospective study. Setting Obstetric unit, Dudley Road Hospital, Birmingham, UK. Subjects Six hundred and ninety-two healthy nulliparous women and 11 women with chronic hypertension antedating pregnancy. Main outcome measures 1. Differences in maternal characteristics and obstetric outcome among women with gestational (nonproteinuric) hypertension by the ISSHP criteria, meeting (and failing to meet) the Redman and Jefferies' blood pressure criteria. 2. The proportion of women classified as normal, proteinuric pre-eclampsia, and chronic hypertension on the basis of both Redman and Jefferies' criteria and the current ISSHP criteria. Results There were 55 women with gestational hypertension alone by the ISSHP criteria, of whom 33 met Redman and Jefferies' blood pressure criteria for pre-eclampsia. This group of 33 women had characteristics of nonproteinuric pre-eclampsia, compared with the remaining 22 women in the ISSHP gestational hypertension category who had characteristics of chronic hypertension. The group of 33 were significantly younger and less obese, had significantly lower blood pressure at their first antenatal visit and their obstetric outcome was poorer. The Redman and Jefferies' blood pressure criteria identified as normal 99.5% (95% CI, 98.6% to 99.9%) of women who were also characterised as normal on the basis of the ISSHP criteria (622/625). There were 12 women with proteinuric pre-eclampsia by the ISSHP criteria of whom 11 (92%; 95% CI, 62% to 99.8%) met Redman and Jefferies' blood pressure criteria for pre-eclampsia. None of the 11 women with chronic hypertension antedating pregnancy met these criteria. Conclusions In this population the blood pressure criteria for pre-eclampsia proposed by Redman and Jefferies select women with features of pre-eclampsia (i.e., proteinuria and relatively poor outcome) and, in particular, they enable a distinction to be made between nonproteinuric pre-eclampsia and other causes of gestational hypertension.