The aims of this study were to evaluate differences between women with carpal tunnel syndrome (CTS) and symptom onset in pregnancy (pregnancy cohort) and women with idiopathic CTS (control cohort) and to report changes in symptoms assessed by the Levine Boston Questionnaire (BQ) administered by phone 3 years after diagnosis. Forty-five pregnant women with CTS (mean age 32 +/- 3.9 years) and 90 age-matched women with idiopathic CTS were consecutively enrolled. Diagnosis was based on clinical findings and abnormal transcarpal median nerve conduction. Univariate analysis showed that the pregnancy cohort had a shorter duration of symptoms, higher frequency of bilateral symptoms and non-blue-collar workers, and lower clinical and electrophysiological severity evaluated by ordinal scales and BQ scores. Multivariate analysis showed that the pregnancy cohort had a probability of improvement of symptoms 3-4 times greater than the control cohort. The need for further treatment depended on BQ functional score; 50% of pregnant women had tolerable CTS symptoms and 85% did not require further treatment 3 years after diagnosis, whereas 72% of women in the control cohort did not require long-term therapy. The probability of need for CTS treatment did not depend on the cohort, but only on the severity of hand disability.