Pain experience during chorionic villus sampling and amniocentesis: a preliminary study

To investigate the maternal perception of pain before and after amniocentesis (AC) or transabdominal chorionic villus sampling (TA-CVS).

Three hundred women were divided into groups of 100 participants destined to undergo three different fetal sampling procedures: amniocentesis (group 1), transabdominal chorionic villus sampling (CVS) with a 19 gauge Blache needle (group 2) and transabdominal CVS with a 20 gauge needle (group 3). The visual analog scale (VAS) was used to quantify the patient's pre-sampling expected pain level and the real pain level was measured immediately after the sampling procedure. The factors liable to influence the VAS score after the sampling procedure were studied by single and multivariate analysis and concerned either the sampling procedure or patient demographic data.

The VAS scores obtained before the procedure were not significantly different for the three sampling groups. When performed with a 19 gauge Blache needle TA-CVS is significantly more painful than the other sampling procedures (p=0.0002): VAS score of 3.62 (group 2), 2.49 (group 3) and 2.68 (group 1) for CVS with 20 gauge needle and amniocentesis. Multivariate analysis identified a group of patients for which the perception of pain induced by sampling was higher compared to the other patients: nulliparous patients, having undergone 19 gauge Blache needle CVS, with a high pre-sampling VAS score.

Transabdominal chorionic villus sampling with a 19 gauge Blache needle seems to be the most painful sampling procedure. We question the need to use a 19 gauge needle as acceptable results are obtained with a 20 gauge needle.