title: The influence of needle and syringe size on chorionic villus sampling of term placentae: a randomised trial.
abstract: OBJECTIVE
  To determine the effect of needle and syringe size on the amount of tissue obtained at chorionic villus sampling
  
  
  METHODS
  Two needle sizes, 18 and 20 gauge, and two syringe sizes 5 mL and 20 mL, were used to assess samples from term post-partum placentae. Each of the four combinations was tested by 25 aspirations. The placentae were divided into 100 grid spaces and each grid space was randomly allocated to a needle/syringe combination. The resulting samples were cleaned to separate the chorionic villi (CV), centrifuged and then weighed.
  
  
  RESULTS
  Significantly more tissue was obtained with an 18-g needle compared with a smaller 20-g needle (median weight difference 1.5 mg, 95% CI 0.8-2.3 mg). More tissue was also obtained with the larger 20-mL syringe though the impact of the syringe size was less than that of the needle size (median difference 0.8 mg, 95% CI 0-1.6).
  
  
  CONCLUSIONS
  A larger syringe and needle size yields a larger quantity of chorionic villi from the post-partum term placenta.
authors.affiliation: Liverpool Women's Hospital, Liverpool, UK.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Cochrane
authors.forename: Magdalen
authors.initials: M
authors.lastname: Ainscough
authors.forename: Zarko
authors.initials: Z
authors.lastname: Alfirevic
mesh_terms: D015193:Chorionic Villi Sampling / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D009339:Needles; D049590:Postpartum Period; D011247:Pregnancy; D013048:Specimen Handling; D013594:Syringes