The prevalence and severity of carpal tunnel syndrome during pregnancy

Background: Carpal tunnel syndrome (CTS) is the most common compression neuropathy of median nerve, which can occur or aggravate during pregnancy and sometimes needs surgery. Since early diagnosis leads to simpler and less risky treatments, this study evaluated the frequency and severity of CTS in pregnancy.
Materials and Methods: In this descriptive cross-sectional study, 100 pregnant women who came to gynecology clinic of university hospitals were randomly selected. At first, they were asked for presence of clinical symptoms, and then clinical tests including Phalen and Tinel were conducted to diagnose CTS. Then, electrodiagnostic studies including sensory and motor distal latencies of median nerve were measured and compared with those of ulnar nerve, and then, nerve conduction velocity of median nerve across wrist was evaluated.
Results: Among the studied pregnant women, 19% had CTS, out of whom 47.5% were bilateral and 26.3% had severe CTS. The prevalence in the first, second, and third trimesters were 11%, 26%, and 63%, respectively, and 42% were asymptomatic. Sensitivity and specificity of clinical signs as compared with electrodiagnostic findings were 52% and 23%, respectively.
Conclusions: The prevalence of CTS is relatively high in pregnant women. The prevalence and severity of CTS increase and the rate of asymptomatic cases reduces with the age of pregnancy. Clinical examination and history taking could not diagnose all cases, and their sensitivity and specificity are much less than electrodiagnostic tests. Therefore, it is recommended that electrodiagnostic studies be conducted in pregnant women during the third trimester.