title: Effect of chorionic villus sampling on uterine artery Doppler.
abstract: BACKGROUND
  The aim of this study was to examine the potential effect of chorionic villus sampling (CVS) on placental perfusion by examining the change in uterine artery pulsatility index (PI) between the first and second trimesters of pregnancy.
  
  
  METHODS
  This was a prospective screening study for pregnancy complications which included measurement of uterine artery PI at 11(+0) to 13(+6) weeks and at 20(+0) to 24(+6) weeks of gestation. In women at increased risk for fetal aneuploidies, CVS was performed. Uterine artery PI in the first and second trimesters, and the change in PI between the two examinations were compared between the CVS and non-CVS groups.
  
  
  RESULTS
  The study population included 8,822 singleton pregnancies, in 308 of which CVS was performed. In the CVS group, compared to the non-CVS group, the median uterine artery PI before CVS, corrected for gestational age, was higher in both the first and second trimesters of pregnancy, but the change in PI between the two examinations was not significantly different (p = 0.789).
  
  
  CONCLUSIONS
  The performance of CVS in the first trimester is unlikely to interfere with normal placentation.
authors.affiliation: Department of Fetal Medicine, Institute for Women's Health, University College Hospital, London, UK. asmakhalil79@googlemail.com
authors.forename: Asma
authors.initials: A
authors.lastname: Khalil
authors.forename: Ranjit
authors.initials: R
authors.lastname: Akolekar
authors.forename: Argyro
authors.initials: A
authors.lastname: Syngelaki
authors.forename: Jose-Maria Perez
authors.initials: JM
authors.lastname: Penco
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D015193:Chorionic Villi Sampling / Q000009:adverse effects*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging / Q000209:etiology*; D011261:Pregnancy Trimester, First; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D016216:Ultrasonography, Prenatal; D055988:Uterine Artery / Q000000981:diagnostic imaging*; D014599:Uterus / Q000098:blood supply / Q000000981:diagnostic imaging