The influence of needle and syringe size on chorionic villus sampling of term placentae: a randomised trial.

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).

CONCLUSION

A larger syringe and needle size yields a larger quantity of chorionic villi from the post-partum term placenta.