Disclosures: N.A. Varnier: None. M. Brown: None. G. Davis: None. F. Pettit: None. G. Mangos: None. A. Henry: None. doi:10.1016/j.preghy.2014.10.045 [42-OR] Diagnostic accuracy of placental growth factor in women with chronic kidney disease or hypertension and sus- pected preeclampsia: A prospective cohort study Kate Bramham a , Paul Seed a , Catherine Nelson-Piercy a , Liz Lightstone b , Lottie Ashford a , James Butler a , Lucilla Poston a , Lucy Chappell a ( a King’s College London, London, United Kingdom, b Imperial College London, London, United Kingdom) Objectives: Women with chronic kidney disease (CKD) and chronic hypertension (CHT) are at increased risk of superim- posed pre-eclampsia (SPE) and associated adverse preg- nancy outcomes. Diagnosis of SPE is challenging in women with CKD or CHT as hypertension and proteinuria exist in women without the condition. Placental growth factor (PlGF) is a secondary marker of associated placental dys- function in pre-eclampsia (PE), with known low plasma con- centrations in the disease. The aim of this study was to explore the role in the diagnosis of SPE in women with CKD or CHT. Methods: Women with CKD or CHT, SPE, PE and low risk controls, were recruited after 20 weeks gestation. Plasma concentrations of PlGF were measured with Alere Triage Ò assay. Proportions of women with low PlGF (<5th Centile) were compared. Results: Samples from 129 women with CKD or CHT, 24 women with PE and 71 healthy controls were analyzed. Area under ROC for low PlGF for the diagnosis of pre-eclampsia and superimposed pre-eclampsia was high. ROC for women with CHT only was 0.89 (SE 0.07) and CKD (with and with- out CHT) was 0.98 (SE 0.02). There was no correlation between serum creatinine and PlGF (R = 0.03, P = 0.74). For women with CHT/CKD, PlGF < 5th Centile for the diagnosis of SPE had high specificity (85.3%) and negative predictive values (96.7%) but lower sensitivity (75%) and positive pre- dictive value (37.5%). Conclusions: Low PlGF is the first test to have such high specificity, positive and negative predictive values for SPE in women with CKD and/or CHT, despite the potential contribution of pre-existing endothelial dysfunction. Fur- ther exploration of the predictive value of PlGF for adverse pregnancy events in women with CKD and/or CHT and its role in cases of diagnostic uncertainty is required. Disclosures: K. Bramham: None. P. Seed: None. C. Nelson-Piercy: None. L. Lightstone: None. L. Ashford: None. J. Butler: None. L. Poston: None. L. Chappell: None. doi:10.1016/j.preghy.2014.10.046 [43-OR] The natural history of gestational hypertension among women hospitalized at <29 weeks Abstracts / Pregnancy Hypertension: An International Journal of Women’s Cardiovascular Health 5 (2015) 2–52 21