Increased nuchal translucency and decreased fetomaternal transfusion after chorionic villus sampling

Abstract

Objective: To investigate the relationship between nuchal translucency (NT) and fetomaternal transfusion (FMT) after chorionic villus sampling (CVS). Methods: The level of FMT was determined in 272 viable, singleton pregnancies in which 10-14-week ultrasound scanning, NT measurement and CVS for fetal karyotyping had been performed. The pre-CVS NT was measured transvaginally, and the women were divided into two groups, i.e. those with NT <2.5 mm (Group 1) or ≥ 2.5 mm (Group 2). The level of FMT was determined via the maternal serum alpha-fetoprotein levels before and after CVS. FMT was analyzed in relation to the pre-CVS NT. Results: Of the 272 pregnancies, 213 were in Group 1 and 59 in Group 2. The mean levels of FMT after CVS were 23.3 ± 12.2 and 5.4 ± 2.9 μL in Groups 1 and 2, respectively (P < 0.01). An FMT < 100 μL was found in 19 cases in Group 1, whereas the maximum in Group 2 was 67.2 μL. Aneuploidies were diagnosed in 17 cases, 15 (88.2%) of them in Group 2. When the pregnancies with adverse outcome were excluded from the two groups, a higher level of FMT was observed in Subgroup 1 than in Subgroup 2 (P < 0.01). Conclusions: The mean level of FMT after CVS was significantly lower in pregnancies with an increased pre-CVS NT, a relationship observed in euploid pregnancies also. An increased pre-CVS NT seems to be inversely correlated with the FMT increase after CVS. Further studies are planned to investigate the background to this phenomenon. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.