Maternal and Perinatal Outcomes According to Proteinuria in Preeclampsia: A Retrospective Cohort Study

INTRODUCTION: The prognostic significance of proteinuria in preeclampsia remains uncertain. This study aimed to compare maternal, laboratory, and perinatal outcomes between women with dipstick proteinuria <2+ and ≥2+ and to evaluate the association between proteinuria ≥2+ and adverse outcomes.
METHODS: This retrospective cohort included 260 women with preeclampsia, categorized according to dipstick proteinuria as <2+ (0/1+; n=126) or ≥2+ (n=134). Maternal, laboratory, and perinatal outcomes were compared between the groups. Binary logistic regression was used to evaluate the association between proteinuria ≥2+ and the composite adverse neonatal outcome, adjusting for maternal age, nulliparity, and severe hypertension.
RESULTS: Dipstick proteinuria ≥2+ was present in 134 women (51.5%). Compared with the <2+ group, women with proteinuria ≥2+ had higher blood urea nitrogen and creatinine levels and lower estimated glomerular filtration rate (all p≤0.013). Median birthweight was lower in the ≥2+ group (2315 vs 2520 g; p=0.002), whereas gestational age at delivery and Apgar scores did not differ significantly. The composite adverse neonatal outcome was more frequent with proteinuria ≥2+ (57.5% vs 44.4%; p=0.036), while severe hypertension and composite adverse maternal outcome rates were similar. Proteinuria ≥2+ was associated with the composite adverse neonatal outcome in the unadjusted analysis (OR 1.69, 95% CI 1.03–2.76; p=0.036) and in the primary adjusted model (adjusted OR 1.74, 95% CI 1.03–2.93; p=0.037). After gestational age at delivery was added in the sensitivity model, the association was attenuated (adjusted OR 1.40, 95% CI 0.72–2.71; p=0.317), while model discrimination increased from an AUC of 0.658 to 0.864.
DISCUSSION AND CONCLUSION: Dipstick proteinuria ≥2+ was associated with greater renal biochemical involvement, lower birthweight, and higher odds of a composite adverse neonatal outcome, but not with severe hypertension or the composite adverse maternal outcome. The attenuation after adjustment for gestational age at delivery suggests that the neonatal association was not independent of the timing of birth.

Keywords: Preeclampsia, Proteinuria, Severe hypertension, Maternal outcomes, Perinatal outcomes, Neonatal outcomes, Dipstick urinalysis