Pregnancy and Kidney Outcomes in Patients With IgA Nephropathy: A Cohort Study

Background: The outcomes of pregnancy in immunoglobulin A nephropathy (IgAN) are controversial. This cohort study assessed the effects of pregnancy on kidney disease progression and risk factors for adverse pregnancy outcomes in patients with IgAN. Study Design: A cohort study. Setting & Participants: Women of child-bearing age with IgAN and minimum follow-up of 1 year after biopsy from December 2003 to September 2014. Predictors: Pregnancy, treated as a time-dependent variable; baseline (at time of biopsy) estimated glomerular filtration rate (eGFR), proteinuria, blood pressure, and kidney pathology (Oxford MEST classification). Outcomes: Kidney disease progression event, defined as 30% decline in eGFR or end-stage kidney disease; rate of eGFR decline; and adverse pregnancy outcomes, including severe preeclampsia and fetal loss. Results: Of 413 patients enrolled, 266 (64.4%), 101 (24.5%), 40 (9.6%), and 6 (1.5%) had chronic kidney disease (CKD) stages 1, 2, 3, and 4, respectively. During follow-up, 104 had 116 pregnancies, of which 110 continued beyond week 20; 309 patients did not become pregnant. After adjustment for age, eGFR, mean arterial pressure, proteinuria, and pathology class at the time of biopsy, subsequent pregnancy among patients with CKD stages 3 to 4, but not CKD stages 1 to 2, was associated with faster eGFR decline (-7.44 vs -3.90 mL/min/1.73 m(2) per year; P = 0.007) and increased incidence of kidney progression events (HR, 5.14; 95% CI, 1.16-22.74) compared with patients who did not become pregnant. Limitations: Relatively small sample size and single-center experience. Conclusions: Pregnancy accelerated kidney disease progression in women with IgAN and CKD stage 3, but not in those at stage 1 or 2. (C) 2017 by the National Kidney Foundation, Inc.