Impact of High Levels of Pregnancy Associated Plasma Protein-A on Pregnancy

Abstract

Introduction: Routinely performed aneuploidy screen takes into account free beta human chorionic gonadotrophins (β-hCG), Pregnancy Associated Plasma Protein-A (PAPP-A), nuchal translucency, and various maternal characteristics. Incidental finding of extreme level of PAPP-A can generate anxiety. Association of low PAPP-A has been established with chromosomal anomalies and adverse pregnancy outcome. The effect of high PAPP-A on feto-maternal outcome has not been widely studied. Aim: The aim of the study was to analyse pregnancy outcome in the group with high maternal PAPP-A, that is >95th centile at the first trimester aneuploidy screen test. Materials and Methods: The prospective observational study was conducted at Dr. TMA Pai hospital, affiliated to Manipal Academy of Higher Education, Manipal. Each patient visiting antenatal OPD was counselled for first trimester aneuploidy screening during the study period of two years (November 2015 to November 2017). All patients who were registered for delivery at the hospital were taken into the study. Blood samples were taken at 11-13+6 weeks of pregnancy. A total of 1500 consecutive pregnancies having first trimester screening were followed up with PAPP-A levels, expressed in Multiple of Medians (MoM). The study group was formed by patients with PAPP-A of more than 95th centile. Only euploid foetuses were considered for the analysis. The pregnancy outcomes were determined in PAPP-A levels of >95th percentiles (3.11 MoM and more) with respect to threatened abortion, preterm delivery, foetal malformations, hypertension in pregnancy, gestational diabetes and growth abnormalities. It was compared with matched control group of PAPP-A between 5th to 95th centile (PAPP-A >0.49 to 3.10). Statistical analysis was performed using Statistical Package for Social Science (SPSS) software version 16 and p-value <0.05 was considered statistically significant. Results: For our grouped data, the incidence of high PAPP-A was 4.6%, and 95th centile value for PAPP-A was 3.10 MoM. The maximum value of PAPP-A recorded was 8.6 MoM. We found no statistically significant difference in the incidence of threatened abortion, preterm delivery, foetal malformations, large for gestation foetuses, gestational diabetes, and hypertension in pregnancy. The incidence of small for gestation was significantly different across the two groups (p-value<0.05). Conclusion: High PAPP-A values are seen less frequently. The pregnant woman with structurally normal foetuses should be informed that there is no reason to be anxious for adverse pregnancy outcome due to high PAPP-A.

Keywords

• foetal growth restriction
• first trimester aneuploidy screen
• growth abnormality
• macrosomia