Pregnancy And Renal Outcomes In Patients With Primary Glomerulonephritis

Background and Objective:Primary glomerulonephritis(PGN)patients are at higher risks of adverse maternal and fetal outcomes and face several challenges during pregnancy due to their increased physiologic demands on the kidney:increased risk of complications such as preeclampsia,preterm delivery and low birth weight,and progression of kidney disease.There are a few studies about pregnancy and renal outcomes in patients with primary glomerulonephritis.We aimed to investigate the risk factors for maternal and fetal outcomes,the effect of pregnancy on renal disease in patients with biopsy-proven primary glomerulonephritis to provide better guidance for preventing or reducing adverse pregnancy outcomes.Methods:We performed a retrospective study of the pregnant patient with biopsy-proven primary glomerulonephritis diagnosed at Qilu Hospital of Shandong University from 2014 to 2021.All cases of pregnancy during primary glomerulonephritis diagnosis or follow-up were included.Clinical manifestations,pathology subtypes,laboratory data,medication,pregnancy outcomes,and renal outcome were collected from medical records.Pearson’s correlation was used to test correlation between preeclampsia,severe preeclampsia,preterm birth,low birth weight and acute kidney injury and several risk factors including maternal age,hypertension,serum creatinine,serum albumin and proteinuria.Results:1.Among 17 patients,mean maternal age at onset of pregnancy was 29.4 ± 4.1 years(range,22-37 years)and mean gestational age at presentation was 16.4±6.0 weeks(range,5-25 weeks).The mean serum creatinine was 0.78 mg/dl and proteinuria was 9.30 g/g at presentation.All patients had a serum creatinine level<1.5 mg/dl.Four patients(24%)had a history of hypertension,12 patients had hematuria(71%),and 14 patients(82%)had nephrotic-range proteinuria at presentation.All 17 patients underwent renal biopsy,including membranous nephropathy(n=6).focal segmental glomerulosclerosis(n=4),minimal change nephropathy(n=3),IgA nephropathy(n=3),and mesangial proliferative glomerulonephritis(n=1).Ten patients were newly diagnosed with primary glomerulonephritis during pregnancy and underwent renal biopsy within one year of delivery.2.During pregnancy,6 pregnancies(35%)complicated by adverse maternal events including gestational new-onset hypertension(1 8%),preeclampsia(18%).The live birth rate was 76%(13/17)and the mean gestational week at delivery was 36.0 ± 2.8 weeks(range,25-40 weeks).Seven pregnancies(41%)complicated by adverse fatal events including preterm deliveries(35%),low birth weight(35%),fetal malformation(12%),etc.Three patients(18%)developed acute kidney injury during pregnancy,2 of 3 patients had renal disease progression at final follow-up after delivery,including 1 reaching end-stage renal disease and performing renal transplantation at final follow-up.3.Proteinuria was significantly correlated with adverse pregnancy events of preeclampsia(P=0.016),severe preeclampsia(P=0.016),preterm delivery(P=0.035)and low birth weight(P=0.035).In the 17 cases whose urinary protein-creatinine ratio at presentation<3.5 g/g,there were 3 cases with no adverse maternal-fetal events,while in the 14 cases with urinary protein-creatinine ratio≥3.5 g/g,there altogether 11 maternal-fetal events including preeclampsia,fetal loss,preterm delivery,low birth weight,fetal malformations and neonatal intensive care unit.Conclusion:1.Primary glomerulonephritis pregnant patients often presented with nephrotic syndrome and hematuria at onset.2.Primary glomerulonephritis patients showed a higher risk of adverse pregnancy outcomes but had relatively stable kidney processes.3.Proteinuria was significantly correlated with adverse maternal-fetal events and heavy proteinuria(urinary protein-creatinine ratio≥3.5 g/g)may predict a higher rate of adverse materno-fetal events.Further studies of larger subjects in the future are urgently needed.