Nuchal translucency measurement, free β-hCG and PAPP-A concentrations in IVF/ICSI pregnancies : systematic review and meta-analysis

So far, data on the effect of assisted reproductive technologies (ART) on the components of first trimester combined screening for Down syndrome are still controversial. A systematic search of the literature was performed in order to identify the effect of ART, particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with fresh embryo transfer, on the nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A measurements. Moreover, a meta-analysis and a descriptive graphical representation of the ratios between ART and spontaneous pregnancies (controls) values of median of the multiple of median (m0MoM) were performed. Free beta-human chorionic gonadotrophin test showed slightly higher values in the ICSI group than controls (RR = 1.09, 95%CI: 1.03–1.16) but not in the IVF group (RR = 1.03, 95%CI: 0.94–1.12). Pregnancy-associated plasma protein-A values for IVF/ICSI, IVF and ICSI showed lower values in comparison with controls (RR, 95%CI 0.85, 0.80–0.90; 0.82, 0.74–0.89 and 0.83, 0.79–0.86, respectively). The nuchal translucency measurement did not show any statistical differences between study groups (IVF and ICSI) and controls (RR = 1.00, 95%CI: 0.94–1.08 and RR = 1.01, 95%CI: 0.97–1.05, respectively). These results may be due to alterations in the placentation of ART pregnancies. Differentiating further subgroups of ART pregnancies may explain the differences in biomarker concentrations, in prenatal behavior and in obstetric outcomes between ART and spontaneous pregnancies.