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British Journal of Obstetrics and Gynaecology June 1992, Vol. 99
CORRESPONDENCE
Susan Bewley Stuart Campbell Professor Department of Obstetrics and Gynaecology King’s College School of Medicine and Dentistry Denmark Hill, London SE5 8RX
clinical, biologic, echographic and velocimetric parameters in cases of retroplacental hematoma. Arch-Mal-Couer 82, 1063-1068. Villar J., de Onis M., Kestler E., Bolanos F., Cerezo R. & Bernedes H. (1 990) The differential neonatal morbidity of the intrauterine growth retardation syndrome. Am J Obstet Gynecoll63, 15 1- 157.
Author’s reply Dear Sir, We made a careful study of the potential value of uterine artery Doppler studies for screening that precisely measured its predictive properties. The four outcomes quoted were examined, and more. We investigated separately the relation of uteroplacental resistance index (RI) to three grades of small-for-gestational-age (SGA) babies, mild, moderate and severe proteinuric and non-proteinuric hypertension, four types of antepartum haemorrhage, three indices of fetal distress, ten other pregnancy outcomes including preterm birth, and five different combinations of the above. All these outcomes were examined for eight cut-offs and three different versions of RI. The abnormal waveforms were not rigidly defined (Table 4 showing the results for eight different cut-offs). High sensitivity was not sacrificed for specificitythe test is not yet acceptable for routine use whatever the level of cutoff, whether chosen for high specificity or high sensitivity. There was no reason to emphasize the 82% sensitivity of predicting proteinuric hypertension at a cut-off that generated a specificity of only 36%. In a routine population, 64% of women would be incorrectly identified as being ‘at-risk’ and 18% of pre-eclamp nd 2 3 8 of ‘severe’ complications would be missed. It is your correspondent who is overvaluing a test that identifies 66% of the pregnant population as ‘at risk’ (and thus requiring more intensive monitoring) whilst still missing 20% of those with disease. The combined endpoints of adverse pregnancy outcome were neither inaccurate nor incomplete. There was a relation between high RI and SGA, proteinuric hypertension, abruption and elective caesarean section at
British Journal of Obstetrics and Gynaecology June 1992, Vol. 99
CORRESPONDENCE
Susan Bewley Stuart Campbell Professor Department of Obstetrics and Gynaecology King’s College School of Medicine and Dentistry Denmark Hill, London SE5 8RX
clinical, biologic, echographic and velocimetric parameters in cases of retroplacental hematoma. Arch-Mal-Couer 82, 1063-1068. Villar J., de Onis M., Kestler E., Bolanos F., Cerezo R. & Bernedes H. (1 990) The differential neonatal morbidity of the intrauterine growth retardation syndrome. Am J Obstet Gynecoll63, 15 1- 157.
Author’s reply Dear Sir, We made a careful study of the potential value of uterine artery Doppler studies for screening that precisely measured its predictive properties. The four outcomes quoted were examined, and more. We investigated separately the relation of uteroplacental resistance index (RI) to three grades of small-for-gestational-age (SGA) babies, mild, moderate and severe proteinuric and non-proteinuric hypertension, four types of antepartum haemorrhage, three indices of fetal distress, ten other pregnancy outcomes including preterm birth, and five different combinations of the above. All these outcomes were examined for eight cut-offs and three different versions of RI. The abnormal waveforms were not rigidly defined (Table 4 showing the results for eight different cut-offs). High sensitivity was not sacrificed for specificitythe test is not yet acceptable for routine use whatever the level of cutoff, whether chosen for high specificity or high sensitivity. There was no reason to emphasize the 82% sensitivity of predicting proteinuric hypertension at a cut-off that generated a specificity of only 36%. In a routine population, 64% of women would be incorrectly identified as being ‘at-risk’ and 18% of pre-eclamp nd 2 3 8 of ‘severe’ complications would be missed. It is your correspondent who is overvaluing a test that identifies 66% of the pregnant population as ‘at risk’ (and thus requiring more intensive monitoring) whilst still missing 20% of those with disease. The combined endpoints of adverse pregnancy outcome were neither inaccurate nor incomplete. There was a relation between high RI and SGA, proteinuric hypertension, abruption and elective caesarean section at
