Prediction of Adverse Obstetric Outcomes by First Trimester Screening with Free β-hCG and PAPP-A: A Prospective Study of 889 Singleton Pregnancies

Abstract

Aim: We aimed to analyze the association of first-trimester screening biomarkers (PAPP-A and free β-hCG) that correspond specific percentile with adverse pregnancy outcomes, including preterm labor, preterm delivery, gestational diabetes mellitus (GDM), gestational hypertension, preeclampsia, low birth weight (LBW), small for gestational age (SGA), large for gestational age (LGA), intrauterine growth restriction (IUGR), macrosomia, and intrauterine exitus (IUEX). Materials and Method: This prospective study conducted between 1st May 2011 and 1st May 2012 at Gazi University Faculty of Medicine, Turkey. We recruited only singleton pregnancies. The first-trimester screening test was performed between 11-14 weeks of gestation. Results: Eight hundred eighty-nine of them met the inclusion criteria for our study. The median age was 29 (26-33) years. Median free β-hCG MoM and PAPP-A MoM were 1.0 (0.7 - 1.48) and 1.04 (0.73 - 1.46), respectively. The most common adverse obstetric outcomes were preterm labor 164 (18.4%), threatened abortion 95 (10.7%), and GDM 75 (8.4%). There was a linear trend with PAPP-A MoM and SGA, LBW, preterm delivery (p=<0.0000001, 0.033, and 0.03, respectively). When PAPP-A MoM results were categorized under three groups as ≤0.42 (5th percentile), >2.5 (95th percentile), and 0.73-1.47 (25th -75th), a significant difference between there groups were detected for SGA (<0.0000001), LBW (0.01), IUEX (0.00005), preterm labor (0.002), IUGR (0.006). Only preterm labor showed a significant linear trend for β-hCG MoM values (p =0.007). However, this significance was not detected when β-hCG MoM values were categorized as ≤0.40 (5th percentile), >2.9 (95th percentile), and 0.75-1.49 (25th -75th) (p=0.47). The correlation coefficient of birth weight and PAPP-A MoM was 0.133, which is negligible (p=0.0001). Conclusion: Our study suggested the possibility of predicting the women with the risk of adverse obstetric outcomes by using first-trimester screening biomarkers, namely maternal free β-hCG, and PAPP-A levels.