Data from: Efficacy and safety of one hour versus four hour blood pressure profile with clinical and laboratory assessment for the exclusion of gestational hypertension and pre-eclampsia: a retrospective study in a university affiliated maternity hospital

Objective: We asked whether 60 compared with 240 minutes observation is sufficiently informative and safe for pregnancy day assessment (PDAC) of suspected pre-eclampsia (PE). Design: A retrospective study of 209 pregnant women (475 PDAC assessments) over 6 months with routinely collected blood pressure, symptom and laboratory information. We proposed a 60 minute screening algorithm comprising: absence of symptoms, normal laboratory parameters and ≤1high blood pressure reading (SBP 140 mmHg or higher or DBP 90mmHg or higher). We also evaluated two less inclusive screening algorithms. We determined short term outcomes (within 4 hours): severe hypertension, proteinuric hypertension and pregnancy induced hypertension, as well as long-term outcome: PE-related diagnoses up to the early puerperium. We assessed performance of alternate screening algorithms performance using 2x2 tables. Results: 1 in 3 women met all screen negative criteria at 1 hour. Their risk of hypertension requiring treatment in the next 3 hours was 1.8% and of failing to diagnose proteinuric hypertensive PE at 4 hours was 5.1%. If BP triggers were 5 mmHg lower, 1 in 6 women would be screen-negative of whom 1.1% subsequently develop treatment-requiring hypertension and 4.5% demonstrate short-term proteinuric hypertension. We present sensitivity, specificity, negative and positive likelihood ratios for alternate screening algorithms. Conclusion: We endorse further research into the safest screening test where women are considered for discharge after 60 minutes. Safety, patient and staff satisfaction should be assessed prospectively. Any screening test should be used in conjunction with good clinical care to minimise maternal and perinatal hazards of pre-eclampsia.