Effectiveness and safety of 1 vs 4 h 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 min 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, 6 months) with routinely collected blood pressure (BP), symptom and laboratory information. We proposed a 60 min screening algorithm comprising: absence of symptoms, normal laboratory parameters and ≤1high-BP reading (systolic blood pressure, SBP 140 mm Hg or higher or diastolic blood pressure, DBP 90 mm Hg or higher). We also evaluated two less inclusive screening algorithms. We determined short-term outcomes (within 4 h): 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 2×2 tables. RESULTS: 1 in 3 women met all screen negative criteria at 1 h. Their risk of hypertension requiring treatment in the next 3 h was 1.8% and of failing to diagnose proteinuric hypertensive PE at 4 h was 5.1%. If BP triggers were 5 mm Hg lower, 1 in 6 women would be screen-negative of whom 1.1% subsequently develops treatment-requiring hypertension and 4.5% demonstrate short-term proteinuric hypertension. We present sensitivity, specificity, negative and positive likelihood ratios for alternate screening algorithms. CONCLUSIONS: We endorse further research into the safest screening test where women are considered for discharge after 60 min. 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 PE.