Pregnancy in chronic kidney disease: need for a common language

Introduction: Chronic kidney disease (CKD) is a growing health care problem, affecting 3% of women of childbearing age. Aim: This study attempted to systematically review the literature for 2000-2009 on pregnancy in CKD, as a guide for counseling. Methods: Data sources included a Medline search for 2000-2009, employing MESH and free terms on pregnancy and CKD, limited to humans and English-language publications. Only studies observing at least 25 pregnancies were considered. The bibliographic search, abstract screening and data extraction were performed in duplicate. Out of over 3,000 references and 276 full texts, 23 studies fulfilled the selection criteria; 3 were added from references. Results: The 26 studies reported on over 2,000 pregnancies. Five main categories were identified: CKD (399 pregnancies, excluding 2 population studies), lupus nephropathy (431 pregnancies), diabetic nephropathy (386 pregnancies), hematuria (310 pregnancies), kidney donors (586 pregnancies) and other. Definitions of diseases, outcomes and stratifications were nonhomogeneous, thus impairing meta-analytic pooling and quantification of the risks. Within these limits, 3 major qualitative determinants of outcome were confirmed as relevant in all subsets: CKD stage, hypertension and proteinuria. Their combination may multiply the interrelated major risks (for the mother: preeclampsia, renal function impairment and proteinuria; for the offspring: small babies, prematurity, death). Specifically, mothers with lupus nephritis have a relevant risk of death (1.15%), and share with diabetic nephropathy, the risk for perinatal death (up to 23% in lupus, 10% in diabetes). Malformations were not increased, except for urinary tract malformation in reflux nephropathy. Conclusions: There is a strong need to unify definitions and stratifications to allow quantitative evidence-based counseling for pregnant patients with CKD.