['A previous study demonstrated that the increase in diastolic blood pressure during pregnancy was reduced by supplementation with magnesium. The present study was undertaken to explore if increases in diastolic blood pressure could be useful for early identification of pre-eclampsia.', 'Hospital records of nulliparous, singleton normal pregnancies (n = 100) and those diagnosed with pre-eclampsia (n = 109) were obtained from a register at an antenatal health care unit. Data on blood pressure at the regular visits to the unit were collected and analysed.', 'The systolic and diastolic blood pressures were significantly higher at pregnancy week 12 among those who developed pre-eclampsia (p = 0.046 and 0.001, resp). An increase in diastolic blood pressure ≥15 mmHg occurred more frequently among women with pre-eclampsia. In 93 % of the cases, this increase was present before and at the same time as the clinical diagnosis of pre-eclampsia was established.'] Is diastolic blood pressure increase a risk indicator for pre-eclampsia?