P11.11: True value of the biochemical tests of genetic screening in the first trimester combined with highly-trained ultrasound personnel

Abstract

Background: First-trimester Down syndrome screening may have a higher false positive rate in pregnancies achieved by in-vitro fertilization (IVF). Objective: To determine the levels of first-trimester screening markers and to assess the false-positive rate for first-trimester combined screening for Down syndrome in pregnant women after invitro fertilization (IVF), including IVF with intracytoplasmic sperm injection (IVF-ICSI), compared with those observed in spontaneously pregnancies. Methods: A retrospective cohort study of 638 pregnancies achieved after IVF was compared with a control group of 9756 pregnancies conceived spontaneously. All women completed a first-trimester combined screening program. Results: In chromosomally normal pregnancies conceived after IVF, the median value of pregnancy-associated plasma protein-A multiples of the median (MoM) was significantly decreased when compared with pregnancies conceived spontaneously (0.87 vs 1.05), whereas the median free β-human chorionic gonadotropin MoM value was significantly increased (0.90 vs 0.86). The median nuchal translucency thickness MoM was similar in both groups. The false-positive rate of first-trimester combined screening in the overall IVF group, adjusted for maternal age, was significantly higher when compared with controls (9.0% vs. 3.9%). Conclusions: It seems advisable to establish specific median curves for the first-trimester serum screening parameters for IVF pregnancies, as reported in other series.