A COMPARISON OF 2ND-TRIMESTER URINARY ELECTROLYTES, MICROALBUMIN, ANDN-ACETYL-BETA-GLUCOSAMINIDASE FOR PREDICTION OF GESTATIONAL HYPERTENSION AND PREECLAMPSIA

Objective: To evaluate second trimester urinary electrolyte, microalbu min, and enzyme (N-acetyl-beta-glucosaminidase) excretion as predictor s of gestational hypertension and preeclampsia (PET), and to compare r andom with 24-h urine collections. Subjects: 200 primagravid Chinese w omen who were normotensive at booking had measurements performed on bo th random and 24-h urine samples in the second trimester. Outcome Meas ures: Development of nonproteinuric (gestational) hypertension or prot einuric hypertension (PET) during the antenatal period. Results: Twent y-two pregnancies developed gestational hypertension and 8 PET. Twenty -four-hour (but not random) urine calcium/creatinine (Ca/Cr) ratios we re significantly lower in patients who developed PET. The optimal cuto ff value for Ca/Cr ratio for prediction of PET was equivalent to 0.3 m mol/mmol Cr at 22 weeks of gestation (Youden index = 0.39). Urine NAG/ Cr ratios (both random and 24-h) were significantly higher in patients who developed antenatal PET than in normotensive pregnancies or those complicated by gestational hypertension. Twenty-four-hour urine album in/Cr ratios were also higher in patients who subsequently developed P ET. Receiver operating characteristic (ROC) curves show that NAG/Cr ra tio is a better predictor of antenatal PET than Ca/Cr or albumin/Cr ra tios. The optimal cutoff value for NAG/Cr ratio was between 50 and 55 U/mmol Cr at 22 weeks of gestation (Youden index = 0.52). Conclusion: Urinary NAG/Cr ratio measured in 24-h or random urine collections in t he second trimester of pregnancy is shown to have potential as a predi ctor of PET, outperforming Ca/Cr and albumin/Cr ratios.