1228 P reeclampsia and other hypertensive disorders of preg- nancy (HDPs) complicate ≤10% of pregnancies and are a major cause of maternal and perinatal morbidity and mor- tality. 1 HDPs include chronic hypertension, gestational hyper- tension, and preeclampsia; associated complications include eclampsia and other end-organ dysfunction, fetal growth restriction, stillbirth, preterm delivery, and neonatal morbid- ity. 1,2 There is considerable clinical variability with regards to severity of disease. 3 The ability to predict which pregnancies complicated by HDPs will go on to develop adverse outcomes (that is, the prognosis of women with HDPs) would help to improve disease management, including timing of delivery, and prevent adverse outcomes. 4,5 Although the pathophysiology of the disease remains complex, several studies have established that the placenta plays an essential role in the development of the HDPs, especially preeclampsia. 6–8 Many studies have reported that there is an angiogenic imbalance in pregnancies complicated by preeclampsia and intrauterine growth restriction. 9–11 In such pregnancies, concentrations of proangiogenic factors, such as PlGF (placental growth factor) and VEGF (vascu- lar endothelial growth factor), are decreased in the mater- nal circulation, whereas antiangiogenic factors, such as sFlt-1 (soluble fms-like tyrosine kinase-1), also known as VEGFR-1 (VEGF receptor 1), and sENG (soluble endoglin), are increased. 1,6 These fndings have led to speculation that angiogenic factors might be useful in both the prediction of preeclampsia and prognosis with respect to the occurrence of related adverse outcomes. 7,12 The majority of studies of PlGF testing have focused on either prediction of preeclampsia or confrmation of the diag- nosis once preeclampsia is suspected, included in the review Abstract—The PlGF (placental growth factor) has been largely demonstrated to be associated with the diagnosis of the hypertensive disorders of pregnancy (HDPs); however, it is unclear how useful it is for the prognosis of the condition. Our objective was to provide a summary of important fndings of its prognostic ability by systematically reviewing studies that examined the ability of the PlGF, either independently or combined with other factors, to predict maternal and fetal complications resulting from the HDPs. We included studies published before January 30, 2017, reporting on the use of the PlGF as a prognostic test for women with confrmed HDPs or suspected preeclampsia. Of the 220 abstracts identifed through MEDLINE, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature), 17 studies were eligible for our review. Prognostic performance was evaluated by sensitivity, specifcity, likelihood ratios, and area under the receiver operating characteristic curve. PlGF showed moderate-to-high evidence (likelihood ratios of ≥5 or ≤0.2 or area under the receiver operating characteristic curves ≥0.70) for identifying women at the highest risk of preterm delivery or neonatal outcomes (10/12 studies) but showed no clinically useful performance for the prediction of adverse maternal outcomes. PlGF may aid in the management of women with HDPs to avert fetal complications. Future studies should determine an optimum threshold for the marker to guide delivery and should examine whether its use for predicting adverse maternal outcomes in women with HDPs can be improved. (Hypertension. 2017;70:1228-1237. DOI: 10.1161/HYPERTENSIONAHA.117.10150.) • Online Data Supplement Key Words: angiogenic factors hypertensive disorders of pregnancy ■ placental growth factor ■ prediction ■ preeclampsia ■ prognosis ■ systematic review Received August 7, 2017; fnal revision received August 21, 2017; revision accepted September 27, 2017. From the Department of Obstetrics and Gynaecology (U.V.U., J.A.H.), Department of Anesthesiology, Pharmacology, and Therapeutics (B.P., J.M.A.), School of Population and Public Health (M.D.H.), and Woodward Library (H.B.), University of British Columbia, Vancouver, Canada; Healthy Starts Theme, BC Children’s Hospital Research Institute, Vancouver, Canada (U.V.U., J.A.H., B.P., J.M.A.); Nuffeld Department of Obstetrics and Gynaecology, University of Oxford, United Kingdom (M.V.); and School of Life Course Sciences, King’s College London, United Kingdom (L.A.M., P.v.D.). The online-only Data Supplement is available with this article at http://hyper.ahajournals.org/lookup/suppl/doi:10.1161/HYPERTENSIONAHA. 117.10150/-/DC1. Correspondence to U. Vivian Ukah, Department of Obstetrics and Gynaecology, University of British Columbia, 950 W 28th Ave, V5Z 4H4, Vancouver, British Columbia, Canada. E-mail vivian.ukah@cw.bc.ca © 2017 The Authors. Hypertension is published on behalf of the American Heart Association, Inc., by Wolters Kluwer Health, Inc. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial-NoDerivs License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is noncommercial, and no modifcations or adaptations are made. Placental Growth Factor as a Prognostic Tool in Women With Hypertensive Disorders of Pregnancy A Systematic Review U. Vivian Ukah, Jennifer A. Hutcheon, Beth Payne, Matthew D. Haslam, Manu Vatish, J. Mark Ansermino, Helen Brown, Laura A. Magee, Peter von Dadelszen Hypertension is available at http://hyper.ahajournals.org DOI: 10.1161/HYPERTENSIONAHA.117.10150 Pregnancy and Hypertension