Guidelines—similarities and dissimilarities: a systematic review of international clinical practice guidelines for pregnancy hypertension

Abstract

This study aimed to review pregnancy hypertension clinical practice guidelines to inform international clinical practice and research priorities. Relevant national and international clinical practice guidelines, 2009-19, published in English, French, Dutch or German. Following published methods and prospective registration (CRD42019123787), a literature search was updated. CPGs were identified by 2 authors independently who scored quality and usefulness for practice (Appraisal of Guidelines for Research and Evaluation II instrument), abstracted data, and resolved any disagreement by consensus. Of note, 15 of 17 identified clinical practice guidelines (4 international) were deemed "clinically useful" and had recommendations abstracted. The highest Appraisal of Guidelines for Research and Evaluation II scores were from government organizations, and scores have improved over time. The following were consistently recommended: (1) automated blood pressure measurement with devices validated for pregnancy and preeclampsia, reflecting increasing recognition of the prevalence of white-coat hypertension and the potential usefulness of home blood pressure monitoring; (2) use of dipstick proteinuria testing for screening followed by quantitative testing by urinary protein-to-creatinine ratio or 24-hour urine collection; (3) key definitions and most aspects of classification, including a broad definition of preeclampsia (which includes proteinuria and maternal end-organ dysfunction, including headache and visual symptoms and laboratory abnormalities of platelets, creatinine, or liver enzymes) and a recognition that it can worsen after delivery; (4) preeclampsia prevention with aspirin; (5) treatment of severe hypertension, most commonly with intravenous labetalol, oral nifedipine, or intravenous hydralazine; (6) treatment for nonsevere hypertension when undertaken, with oral labetalol (in particular), methyldopa, or nifedipine, with recommendations against the use of renin-angiotensin-aldosterone inhibitors; (7) magnesium sulfate for eclampsia treatment and prevention among women with "severe" preeclampsia; (8) antenatal corticosteroids for preterm birth but not hemolysis, elevated liver enzymes, and low platelet count syndrome; (9) delivery at term for preeclampsia; (10) a focus on usual labor and delivery care but avoidance of ergometrine; and (11) an appreciation that long-term health complications are increased in incidence, mandating lifestyle change and risk factor modification. Lack of uniformity was seen in the following areas: (1) the components of a broad preeclampsia definition (specifically respiratory and gastrointestinal symptoms, fetal manifestations, and biomarkers), what constitutes severe preeclampsia, and whether the definition has utility because at present what constitutes severe preeclampsia by some guidelines that mandate proteinuria now defines any preeclampsia for most other clinical practice guidelines; (2) how preeclampsia risk should be identified early in pregnancy, and aspirin administered for preeclampsia prevention, because multivariable models (with biomarkers and ultrasonography added to clinical risk markers) used in this way to guide aspirin therapy can substantially reduce the incidence of preterm preeclampsia; (3) the value of calcium added to aspirin for preeclampsia prevention, particularly for women with low intake and at increased risk of preeclampsia; (4) emerging recommendations to normalize blood pressure with antihypertensive agents even in the absence of comorbidities; (5) fetal neuroprotection as an indication for magnesium sulfate in the absence of "severe" preeclampsia; and (6) timing of birth for chronic and gestational hypertension and preterm preeclampsia. Consistent recommendations should be implemented and audited. Inconsistencies should be the focus of research.