Reducing pain with genetic amniocentesis—A randomized trial of subfreezing versus room temperature needles

Objective. To determine whether pain associated with second trimester genetic amniocentesis is decreased by using subfreezing rather than room temperature needles. Methods. Subjects were randomized to a −14°C or room temperature (20–22°C) 22-gauge spinal needle. Patients, blinded to allocation, recorded anticipated and actual pain before and after the procedure, respectively, using a 0–10 visual analog scale with 0 = no pain and 10 = excruciating pain. Results. Thirty-three subjects were randomized to room temperature and 29 subjects to subfreezing needles. Anticipated pain was similar in room temperature, 5.1 ± 1.7, and subfreezing groups, 4.9 ± 2.0, respectively (p = 0.6). Actual pain was also similar in the room temperature, 3.6 ± 2.0, and subfreezing groups, 2.8 ± 2.0, respectively (p = 0.14). Similar numbers of subjects in the room temperature and subfreezing groups reported less actual pain (20 vs. 18), greater actual pain (4 vs. 4) or no difference in pain (9 vs. 5) than anticipated (p = 0.6). Conclusion. A subfreezing 22-gauge spinal needle does not decrease perceived pain associated with second trimester genetic amniocentesis.