Association of Low-Protein Supplemented Diets with Fetal Growth in Pregnant Women with CKD

Background and objectives Women affected by CKD increasingly choose to get pregnant. Experience with low-protein diets is limited. The aim of this study was to review results obtained from pregnant women with CKD on supplemented vegan–vegetarian low-protein diets. Design, setting, participants, & measurements This was a single-arm, open intervention study between 2000–2012 of a low-protein diet in pregnant patients with stages 3–5 CKD or severe proteinuria (>1 g/d in the first trimester or nephrotic at any time). Stages 3–5 CKD patients who were not on low-protein diets for clinical, psychologic, or logistic reasons served as controls. The setting was the Obstetrics-Nephrology Unit dedicated to kidney diseases in pregnancy. The treated group included 24 pregnancies—21 singleton deliveries, 1 twin pregnancy, 1 abortion, and 1 miscarriage. Additionally, there were 21 controls (16 singleton deliveries, 5 miscarriages). The diet was a vegan–vegetarian low-protein diet (0.6–0.8 g/kg per day) with keto-acid supplementation and 1–3 protein-unrestricted meals allowed per week. Results Treated patients and controls were comparable at baseline for median age (35 versus 34 years), referral week (7 versus 8), eGFR (59 versus 54 ml/min), and hypertension (43.5% versus 33.3%); median proteinuria was higher in patients on the low-protein diet (1.96 [0.1–6.3] versus 0.3 [0.1–2.0] g/d; P P =0.05). Throughout follow-up (6 months to 10 years), hospitalization rates and prevalence of children below the third percentile were similar in both groups. Conclusion Vegan–vegetarian supplemented low-protein diets in pregnant women with stages 3–5 CKD may reduce the likelihood of small for gestational age babies without detrimental effects on kidney function or proteinuria in the mother.