To evaluate the role of plasma volume expansion on 1-year infant outcome after severe hypertensive disorders of pregnancy and to determine prognostic factors for adverse neurodevelopmental infant outcome. Randomised controlled trial, observational prognostic study. Two university hospitals in Amsterdam, The Netherlands. One hundred and seventy-two infants alive of 216 mothers with severe hypertensive disorders of pregnancy who were randomised for a temporising management strategy with or without plasma volume expansion. At 1 year of corrected age, a neurological examination according to Bayley (mental development index [MDI] and psychomotor development index [PDI]) and Touwen was performed. Adverse neurodevelopmental infant outcome was defined as a MDI/PDI score below 70 and/or an abnormal Touwen. Risk factors for adverse neurodevelopmental outcome were explored by univariate and multivariate analyses. Adverse neurodevelopmental infant outcome was observed in 31 infants (18%). There were no differences between the randomisation groups. In multivariate analysis, an association with abnormal umbilical artery/middle cerebral artery Doppler ratio higher than the median, major neonatal morbidity, higher education of the parents, multiparity and Caucasian ethnicity was observed. Nearly 70% of the infants were alive at 1 year without adverse neurodevelopmental outcome. Maternal plasma volume expansion during pregnancy has no effect on 1-year infant outcome. The prediction of adverse outcome at 1 year by perinatal parameters is limited.