First trimester prenatal screening in multiple pregnancies. Part I: comparative analysis of serum proteins PAPP-A and p-hCG in pregnancies conceived spontaneously or by in vitro fertilization

Introduction. Serum proteins PAPP-A (pregnancy-associated plasma protein-A) and β-hCG (the в-subunit of human chorionic gonadotropin) levels are components of the 1st trimester combined screening aimed to detect fetal aneuploidies. In contrast to singleton pregnancies, where the values are well established, this is not the case in twins. Aim : a comparative analysis of serum proteins PAPP-A and β-hCG levels, as well as parameters PAPP-A MoM and β-hCG MoM in the first trimester during pregnancy with dichorionic diamniotic twins that occurred spontaneously or as a result of in vitro fertilization (IVF). Materials and methods . The study group included multiple pregnancies as a result of IVF procedure (n = 100) and spontaneous multiple pregnancies (n = 121) considered as controls. The levels of PAPP-A, β-hCG, PAPP-A MoM and β-hCG MoM were compared using nonparametric Mann-Whitney U test. Results. The PAPP-A MoM level resulted higher in the group of IVF twins (p = 0,007) compared to spontaneous twins: 1.28 [0.97; 1.89] vs. 1.12 [0.87; 1.40] (median [interquartile range]). There were no statistically significant differences in в-hCG levels between the groups of IVF twins and spontaneous twins. Conclusion. The results justify the need for further study of PAPP-A and β-hCG to establish their association with adverse outcomes in both groups of multiple pregnancies.