Microalbuminuria is a predictor of adverse pregnancy outcomes including preeclampsia

Abstract

Objectives: Abnormal urinary protein loss is a marker associated with a diverse range of renal diseases including preeclampsia. Current measures of urine protein used in the diagnostic criteria for the diagnosis of preeclampsia includes urine protein:creatinine ratio and 24-h urine protein. However very little is known about the value of urine albumin:creatinine ratio (uACR) in pregnancy. In this study we examined the prognostic value of microalbuminuria detected antepartum to predict adverse pregnancy outcomes.

Design: This is a single-centre retrospective analysis of 84 pregnant women over the age of 16 attending a tertiary 'high-risk' pregnancy outpatient clinic between July 2010 and June 2013. Utilising medical records, antepartum peak uACR level and pregnancy maternal and fetal outcomes were recorded.

Findings: The primary outcome was a composite of poor maternal and fetal outcomes including preeclampsia, maternal death, eclampsia, stillbirth, neonatal death, IUGR, premature delivery and placental abruption. As the antepartum peak uACR level (in mg/mmol) increased from normoalbuminuria (uACR<3.5) to microalbuminuria (uACR 3.5-35) to macroalbuminuria (>35), the percentage of women with the primary composite outcome increased in a stepwise fashion (13.8% to 24.1% to 62.1% respectively, p<0.001). After adjusting for covariates including history of hypertension, chronic kidney disease and aspirin therapy during pregnancy, micro- and macroalbuminuria remained significant predictors of the primary outcome.

Conclusions: We have shown that antepartum peak uACR is a useful simple marker to help predict adverse maternal and fetal outcomes. Further studies are required to utilise uACR as a prognostic tool in pregnancy before it can be applied in clinical practice.

Keywords: Albumin:creatinine ratio; Microalbuminuria; Preeclampsia; Pregnancy; Proteinuria.