A Randomized Trial to Determine if Local Anesthesia Decreases Pain Perception in Women Undergoing Chorionic Villus Sampling

Chorionic villous sampling (CVS) is a frequent procedure used for antenatal genetic testing. This procedure is associated with anxiety and fear of pain that can be expected during the procedure, often prejudicing patients against this definitive antenatal testing. It is important to determine if different approaches to pain and anxiety reduction are effective. Previous studies have not shown that local anesthesia affects pain experience during amniocentesis (1-5). There are no randomized studies evaluating interventions for pain reduction during chorionic villous sampling which constitutes an important evidence gap.

The study will be offered to women at <13 weeks gestation, with a singleton fetus who are seen at Mount Sinai Medical Center for chorionic villous sampling. The eligible women will be randomized to one of two groups: use of analgesia using injectable lidocaine or ethyl chloride topical anesthetic spray. This study intends to show that local anesthesia during chorionic villous sampling will not decrease the perception of pain in patients undergoing this procedure.

This trial is trying to determine perception of pain based on use of injectable lidocaine or ethyl chloride anesthetic spray; it is noted that the form of anesthesia may be a factor in perception of pain. The investigators do not know if there is a difference in perception for topical or injectable. If the perceived pain is comparable in topical and injectable, this trial could conclude that both are viable options, and while both present minimal risk to patients, topical is less invasive.