EP04.20: Increased rates of pregnancy complications after positive screening results

Methods. This was a prospective study on screening for FA and pSGA in 3504 singleton pregnancies by an algorithm that combines maternal factors, mean arterial pressure, maternal serum biochemistry (free b-hCG and PAPP-A), ultrasound markers (nuchal translucency thickness, tricuspid valve and ductus venosus flow, nasal bone), and uterine artery pulsatility index at 11-13 weeks' gestation at Fetal Medicine Center (Russia). We excluded 1428 cases because of loss to follow-up (n = 1269) and fetal chromosomal and strucrural abnormalities (n=159). With the proposed cut-offs of ≤1:100 for trisomies, and ≤1:150 for pSGA the study population of 2076 was divided into: Group 1: False-positive (FP) for fetal aneuploidy (n=55), including cases with low (n=23) and high (n=32) risk for pSGA; Group 2: low-risk for FA and pSGA (n=1563).