Purpose: To determine whether maternal serum placental growth factor (PlGF) is more effective as a biomarker in predicting the occurrence of early onset preeclampsia in first trimester or early second trimester of pregnancy.
Methods: A prospective cohort study was conducted on women with singleton pregnancies, screened from the antenatal clinic. Serum PlGF estimation was done at 11-14 weeks of gestation on 1,244 women and at 22-24 weeks of gestation on 1,206 women from the initial study population. A cut-off value of <228 pg/ml for serum PlGF at 11-14 weeks of gestation and <144 pg/ml for serum PlGF at 22-24 weeks of gestation were determined by receiver operating characteristic (ROC) curve analysis for identifying pregnant women at risk of developing early onset preeclampsia (<32 weeks of gestation). Univariate logistic regression analysis was used to analyze the association between serum PlGF < 228 pg/ml at 11-14 weeks of gestation and <144 pg/ml at 22-24 weeks of gestation with the occurrence of early onset preeclampsia and odds ratio (OR) was computed. P value < 0.05 was considered statistically significant in this study.
Results: Maternal serum PlGF <144 pg/ml at 22-24 weeks of gestation had a stronger association (OR 18.83; 95 % CI 12.08-22.24; p = 0.000) than serum PlGF <228 pg/ml at 11-14 weeks of gestation (OR 2.76; 95 % CI 1.29-3.94; p = 0.007) with the occurrence of early onset preeclampsia. The sensitivity and specificity of serum PlGF <144 pg/ml at 22-24 weeks of gestation (84 and 78, respectively) were much higher than those of serum PlGF <228 pg/ml at 11-14 weeks of gestation (58 and 66, respectively) in predicting early onset preeclampsia.
Conclusion: Maternal serum PlGF may be more effective as a biomarker in early second trimester than in first trimester of pregnancy, in predicting the occurrence of early onset preeclampsia.