A randomized study to assess two different techniques of aspiration while performing transabdominal chorionic villus sampling

Abstract

Objective The technique used to perform transabdominal chorionic villus sampling (CVS) is not standardized, but aspiration of villi is generally obtained by discontinuous vacuum created in a syringe, manually or by a hand-grip device. We evaluated the feasibility of a new method of performing CVS which employs a 4-mL Vacutainer® connected to the needle, producing a continuous negative pressure. Methods Two hundred pregnant women, whose gestational age ranged from 10 + 2to16 + 2(mean,12 + 1) weeks, entered the randomized study, which was powered to detect with 90% probability the absence of any difference in the size of chorionic samples obtained by using a 20-mL syringe with the vacuum obtained by a hand-grip device (Group 1) or by a vacutainer (Group 2). Four operators with different levels of experience performed all the procedures, which were done transabdominally using a freehand technique with a 20-gauge needle under ultrasound guidance. Results Maternal age, body mass index, gestational age and the way the needle was inserted within the chorion were similar in the two groups. The median amount of villi sampled was 20 mg, with no differences between the two groups. The rate of fetal loss was 1.7%. All losses occurred in women ofGroup 1 who had only one needle insertion. A second needle insertion was required more frequently while using the vacutainer. Conclusion This new technique for performing transabdominal CVS uses a readily available device and is as effective as traditional sampling systems to aspirate villi. It has the advantage of being a one-operator procedure. Copyright © 2008 ISUOG. Published by John Willey & Sons, Ltd.