Effect of pregnancy on median and ulnar nerve conduction

Abstract

INTRODUCTIONPregnancy causes altered function of excitable membranes such as muscle and nerve, due to hormonal changes and edema.1 Carpal tunnel syndrome (CTS) is a frequent complication of pregnancy. The pathology involves the compression of the median nerve passing through the carpal tunnel in the hand. Its prevalence is as high as 62% in some populations during third trimester of pregnancy.2 Available published research points towards various causes of CTS in pregnant woman as influence of hormonal changes, neural oedema, anatomically narrow carpal tunnel etc.2,3 However increase incidence of CTS in woman on regular hormonal contraception and cessation of CTS symptoms in post-partum period suggest the hormonal theory to be true. [2][3][4] Thus to supplement this hypothesis and association of nerve conduction abnormalities with pregnancy, we focused on this research. We failed to find any studies focusing on the issue of nerve conduction during pregnancy, in India. Thus present study aims to see the difference between nerve conduction parameters viz. motor and sensory conduction, in pregnant and non-pregnant women. Our objective was to study the electrophysiological changes in median and ulnar nerve conduction during pregnancy, who have no symptoms of carpal tunnel syndrome during the third trimester in our local population. METHODSThis was a cross-sectional research carried out in randomly selected 30 pregnant women, of any age, in 28-ABSTRACT Background: Pregnancy causes altered function of excitable membranes such as muscle and nerve, due to hormonal changes and edema. We failed to find any studies focusing on the issue of nerve conduction during pregnancy, in India. Thus present study aims to see the difference between nerve conduction parameters viz. motor and sensory conduction, in pregnant and non-pregnant women. Methods: This was a cross-sectional study carried out in randomly selected 30 pregnant women, of any age, in 28-40 weeks of gestation and age matched non-pregnant controls. We studied distal motor latency, compound muscle action potential amplitude, motor nerve conduction velocity, F-minimum latency, sensory latency, sensory nerve action potential amplitude and sensory nerve conduction velocity in bilateral median and ulnar nerves using Aleron-RMS. Results: Present study found no statistically significant difference between motor and sensory conduction of above said nerves in pregnant and nonpregnant women, except F minimum latency of left median nerve in pregnant women and sensory latency of left ulnar nerve in non-pregnant women were prolonged significantly (p<0.05). Conclusions: All motor and sensory parameters of bilateral median and ulnar nerves were normal as compared to non-pregnant controls.