Abstract Objective: The chorionic villus sampling (CVS) technique is not standardized between institutions and can vary greatly between operators. Our goal was to (1) compare the amount of villi obtained by the transabdominal (TA) and transcervical (TC) CVS; (2) compare our single center yield of villi to previously published reports.
Methods: Women undergoing CVS in a singleton pregnancy between 2009 and 2011 were retrospectively identified at a single center. TA CVS was performed using a 20 gauge spinal needle. TC CVS was performed using a 1.4-mm suction catheter. Milligrams of villi and blood from all TA (n=97) and TC (n=36) CVS were obtained. STATA software was used to perform statistical analysis.
Results: The median amount of tissue obtained during a TC CVS [50 mg ; range (5-200 mg)] was higher than the median amount obtained from TA CVS [36 mg; range (8-140 mg)]; p=0.002. There was more blood contamination in the samples obtained using the TC approach (median=10 mg; range 5-40 mg) than in the samples from the TA approach (median=5 mg; range 0-27 mg); p<0.0001. The amount of villi obtained from our institution was significantly higher than has been previously reported [TC (p=0.0001) and TA (p<0.0001)].
Conclusions: TC CVS produced significantly more villi than the TA approach. However, both techniques generated enough villi for direct testing. This information may be useful when multiple genetic tests are being requested. Regardless of route of sampling, the volume of villi obtained was higher at our institution than previously reported. More information regarding amount of villi obtained and relationship to pregnancy complications is needed.
Keywords: Chorionic villus sampling; prenatal diagnosis; transabdominal; transcervical.