EP04.27: First trimester Trisomy 21 screening in Peru

Abstract

Improving our performance in first trimester Down screening. All pregnant women between 11 and 13 weeks were offered first trimester aneuploidy screening in our clinic. Fetal Medicine Foundation (FMF) first trimester soft markers quality published criteria were followed. All the scans were performed by FMF accredited physicians. Pregnant women with basal risk ≥ 1/200 were called high basal risk group (HBRG). Biochemical test (PAPP-a + free beta CGh = BCT) was offered to pregnant women in the HBRG. Cut points for adjusted risk (AR) stratification were ≥ 1/50 (high adjusted risk = HAR) and ≤ 1/1000 (low adjusted risk = LAR) for ultrasound assessment. BCT was offered to pregnant women with AR between 1/50 and 1/1000. An AR ≥ 1/100 in the combined screening test (CST) was considered HAR. Fetuses with nuchal translucency thicker than 3.5mm and those with anomalies were also qualified as HAR. EP04.27: Table 1. BCT sample taken 1499 (57%) 10644 pregnancies were scanned. 757 were excluded (363 inappropriate CRL, 334 twins, 7 not alive, 3 acranea and 51 bleeding controls). 9886 fetuses have risk assessment. There were 35 trisomy 21 and 17 other aneuploidies. More than 25% of the pregnant women were asked for blood testing, but less than 60% of them had them done. Nuchal translucency thicker than 3.5mm help to identify two additional T21 fetuses and 10 with other aneuploidies. DR was estimated in 77% for a False positive rate of 2%. 52 euploid fetuses with mayor anomalies were also identified. Self-financing of health expense limits the quality of aneuploidy screening. Contingent protocols could help to improve it.