Predictive value of urine misfolded protein in preeclampsia in twin pregnancies.

Objective: To assess the utility of urinary misfolded proteins (MP) in predicting preeclampsia (PE) in high-risk twin pregnancies.

Methods: A prospective study was conducted on 600 high-risk twin pregnancies at Shanghai First Maternity and Infant Hospital from March to August 2021. Clinical data were collected, and urinary MP levels were measured. Subsequently, fetal outcomes were monitored. The patients were categorized into three groups based on the presence of PE: unaffected PE group, early-onset PE (ePE) group (gestational age < 34 weeks), and late-onset PE (lPE) group (gestational age ≥ 34 weeks). The predictive value of MP in PE was evaluated using analysis of variance, Chi-square test, and ROC curve analysis.

Results: A total of 464 twin pregnancies were included in the study, among which 66 cases (14.2%) developed PE, including 19 cases of ePE (4.1%) and 47 cases (10.1%) of lPE. Significant differences were found in maternal age, pre-pregnancy body mass index (BMI), BMI ≥ 28 km/m², mean systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), MAP ≥ 85 mmHg, history of PE, history of chronic hypertension, and positive urine protein. The maternal and fetal complications of twin pregnancies with PE were higher than those without PE (P < 0.05). When maternal factors (MF), MAP, and MP were used to predict ePE and lPE alone, the area under the ROC curve of MF was the largest, at 0.739 (95% CI 0.619-0.860) and 0.692 (95% CI 0.603-0.782), respectively. The area under the ROC curve of the combination of the three factors was 0.770 (95% CI 0.703-0.837), higher than that of a single index. In addition, MP predicted the positive predictive value (PPV) and negative predictive value (NPV) of PE from 12 to 15⁺⁶ gestational weeks as 57.9% and 89.2%, respectively; from 16 to 27⁺⁶ gestational weeks as 36.2% and 89.9%, respectively; and during the 12-27⁺⁶ gestational weeks as 42.4% and 92.2%, respectively.

Conclusion: The detection of MP in the urine of women with twin pregnancies is a non-invasive and convenient method for predicting PE. If the test result is positive, enhanced monitoring and timely transfer to a superior hospital are necessary. If the test result is negative, it indicates a low risk of developing PE, reducing the need for excessive clinical examination and intervention.