Median and ulnar nerve conduction in pregnancy.

OBJECTIVE

A prospective, observational study assessed median and ulnar nerve conduction during pregnancy, to identify the optimum test for differentiating physiological effects of pregnancy from pathological carpal tunnel syndrome (CTS).

METHODS

Pregnant women (n=18) and age- and parity-matched non-pregnant controls (n=13) were recruited. Symptomatic and neurophysiological evaluations were performed. Median and ulnar nerve latencies and intrapalmar latency (difference between median and ulnar nerve latencies) were computed.

RESULTS

Median nerve distal latency is more prolonged in pregnant women compared with non-pregnant controls. Median nerve latency is more prolonged in pregnant women with symptoms of CTS than in asymptomatic women. The difference between median and ulnar nerve conduction (normal <0.2 ms) discriminates well between symptomatic and asymptomatic pregnant women.

CONCLUSIONS

Intrapalmar latency is proposed as a useful diagnostic test for classification of carpal tunnel syndrome during pregnancy.