Background: How Canadian practitioners are managing the hypertensive disorders of pregnancy (HDP) is not known, particularly in relation to the 1997 guidelines published by the Canadian Hypertension Society (CHS).
Methods: A survey, with French and English versions (and covering diagnosis, evaluation, and management of pregnancy hypertension), was mailed to all members of the Society of Obstetricians and Gynaecologists of Canada (SOGC) (N = 1757, including obstetricians, family doctors practicing obstetrics, and midwives). Additionally, internists [i.e., all nephrologists (N = 191) and a random sample of 25% of general internists (N = 450)] registered with the Royal College of Physicians and Surgeons of Canada were sampled. The survey was distributed in two mailings and one reminder card. Data were entered into Microsoft Access, and Graph Pad Prism used to summarize responses [N (%)]. Differences in practice between specialties were examined, with a Bonferroni correction used to calculate a significant p value based on the number of comparisons and alpha of 0.05.
Results: Respondents numbered 1187 (49.5%), with 466 not informative for the purpose of the study (due to retirement, or practices that do not include pregnant women with hypertension). The final analysis included 721 completed surveys. For all types of HDP, most internists, family doctors, and midwives initiate nonpharmacological therapy (most common advice to quit work) at dBP 80-89 mmHg (i.e., primary prevention). Only for preeclampsia do obstetricians most frequently use this threshold; otherwise, dBP 90-99 mmHg is usually chosen. For nonsevere hypertension, antihypertensive drug therapy (most commonly methyldopa or labetalol) is started by most practitioners at dBP 90-99 mmHg, although obstetricians are more likely to choose a higher threshold (p < 0.0001). There is little agreement about dBP treatment goal; most internists and family doctors normalize dBP, whereas obstetricians appear to be divided on dBP goals of 80-89 (46-51%) vs. 90-99 mmHg (41-44%) for all HDP (p = 0.66). Severe hypertension is commonly treated with parenteral hydralazine, labetalol, or magnesium sulphate. Short-acting or sustained release nifedipine is used rarely/never by most practitioners. Approximately one-third of obstetricians and family doctors use diazepam to treat eclampsia. The vast majority use MgSO4 prophylactically in women with preeclampsia.
Interpretation: This survey has clarified current stated management of women with HDP, and identified the need for both research into the dBP treatment goal that optimizes pregnancy outcomes among women with HDP, and translation of definitive studies into clinical practice.