This is a multicenter, prospective cohort study including 204 pregnant women, with or without chronic kidney disease (CKD stages 2 to 4). Participants will be enrolled before 14 weeks of gestation. Blood samples (14 mL) will be collected at the 1st, 2nd, and 3rd trimesters and 2 months postpartum for kynurenine measurement, centrally analyzed at CHU Reims using LC-MS/MS. Additional data include maternal demographics, medical and obstetric history, anthropometry, laboratory data (creatinine, hemoglobin, hematocrit, proteinuria), blood pressure, ultrasound (growth parameters, umbilical artery Doppler), and maternal-fetal outcomes (preeclampsia, gestational hypertension, HELLP, hemorrhage, SGA, prematurity, mortality). The primary objective is to compare kynurenine concentrations in the 3rd trimester between women with and without CKD. Secondary objectives include describing longitudinal kynurenine evolution, its association with maternal-fetal outcomes, and modeling kynurenine needs during pregnancy in CKD.
