Immediate changes in umbilical blood flow after transcervical chorionic villus sampling performed by biopsy forceps

Transvaginal ultrasonography with colour Doppler was used to evaluate the immediate changes on the fetal heart rate (FHR) and the fetal umbilical artery pulsatility index (PI) after chorionic villus sampling (CVS). This prospective study included 279 consecutive singleton pregnancies, between 10 and 13 weeks, of women who underwent transcervical CVS in our institution. All Doppler measurements were obtained transvaginally before and immediately after CVS. Structural malformations detected by ultrasound were excluded. Student's t- and Wilcoxon texts were performed for statistical analysis. The results showed no significant decrease in FHR (mean 1.04 beats, t = 1.68, P = 0.94) and a significant elevation of umbilical artery PI (mean 0.12, t = - 6.51, P < 0.001) post-CVS. This difference was only significant in procedures performed at less than 11 weeks' gestation, since there was no significant change for those procedures performed thereafter. These preliminary data suggest that acute fetal haemodynamic changes are induced by CVS and may have clinical effects. Hypotheses on possible vascular mechanisms are discussed. Colour Doppler could widen the possibilities for more accurate in vivo assessment and research on CVS-related placental injury.