Obstet Gynecol Sci.  2013 Jan;56(1):22-28. 10.5468/OGS.2013.56.1.22.

Urinary nephrin: A new predictive marker for pregnancies with preeclampsia and small-for-gestational age infants

• Yang GY
• Lee KA
• Park MH
• Park HS
• Ha EH
• Chun SH
• Kim YJ

• KMID: 1857182
• DOI: http://doi.org/10.5468/OGS.2013.56.1.22

Abstract

OBJECTIVE
The objective of this study was to determine the differences in urinary nephrin among controls, gravidas with preeclampsia (PE), and small-for-gestational age (SGA) infants. We also determined whether or not maternal urinary concentrations of nephrin are associated with the subsequent development of PE and SGA infants.
METHODS
We analyzed maternal urinary levels of nephrin in women who were normal controls (n=50), women who were delivered SGA infants (n=40), and gravidas with PE (n=33) in the first, second and third trimesters. Urinary nephrin concentrations were measured with nephrin enzyme-linked immunosorbent assay kits.
RESULTS
The levels of urinary nephrin were higher in gravida developing preeclampsia or SGA than in controls after adjusting serum creatinine (P<0.05 for both). Maternal urine concentrations of nephrin were higher in pregnancies complicated by SGA and PE in the third trimester (P<0.05), and also higher in pregnancies complicated by SGA in the first trimester (P<0.05). The sensitivity and specificity of nephrin in predicting SGA from normal pregnancies were 67% and 89% in the first trimester, 60% and 79% in the second trimester, and 80% and 84% in the third trimester, respectively. The sensitivity and specificity of nephrin in predicting PE from normal pregnancies were 67% and 83% in the first trimester and 73% and 79% in the third trimester, respectively.
CONCLUSION
We suggest that urinary nephrin can be used as an early marker in pregnancies at risk for developing PE and SGA infants.

Keyword

Nephrin; Small-for-gestational age; Preeclampsia; Urine; Early marker

MeSH Terms

Creatinine
Enzyme-Linked Immunosorbent Assay
Female
Humans
Infant
Membrane Proteins
Pre-Eclampsia
Pregnancy
Pregnancy Trimester, First
Pregnancy Trimester, Second
Pregnancy Trimester, Third
Sensitivity and Specificity
Creatinine
Membrane Proteins

Figure

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  Fig. 1 Urinary nephrin (A) and protein-to-creatinine ratio (B) according to gestational age. The Spearman correlation coefficients were 0.23 (P<0.01) and 0.16 (P=0.051), respectively.

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  Fig. 2 Urinary nephrin (A) and protein-to-creatinine ratio (B) according to the study groups. The SGA and PE groups had higher urinary nephrin levels than controls in the third trimester (P<0.001 and P<0.01, respectively). The urine protein-to-creatinine ratio in the SGA and PE groups were higher than in controls, but failed to reach statistical significance (P>0.1). SGA, small-for-gestational age; PE, preeclampsia.

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  Fig. 3 Receiver operator characteristic curve analysis demonstrating the ability of urinary nephrin to differentiate pregnancies with SGA infants and PE from controls in the first (A, B), second (C), and third (D, E) trimesters. The numbers next to the filled circles represent the nephrin concentration in ng/mL. Cutoff values of 90, 105, and 195 in the first (A), second (C), and third (D) trimesters had 67%, 60%, and 80% sensitivity, respectively, and 89%, 79%, and 84% specificity, respectively, in differentiating pregnancies complicated by SGA infants from controls (AUC [95% CI]: 0.82 [0.67-0.98], 0.72 [0.54-0.90], and 0.87 [0.75-0.99], respectively). Cutoff values of 85 and 135 in the first (B) and third (E) trimesters had 67% and 73% sensitivity, respectively, and 83% and 79% specificity, respectively, in differentiating gravidas with PE from controls (AUC [95% CI]: 0.77 [0.60-0.93] and 0.78 [0.62-0.93], respectively). SGA, small-for-gestational age; PE, preeclampsia; AUC, area under the curve; CI, confidence interval.

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