The authors compare 100 tracings of uterine contractions, recorded using a mobile monitoring apparatus with telephone output TOKOS System), with 100 tracings recorded using static equipment. The TOKOS system is useful in diagnosis of uterine contraction, being equivalent to the reference system. The TOKOS system is superior to the reference system in that it allows the intensity of the contractions to be evaluated. The TOKOS system is an original approach to maternal perception of uterine activity. Overall, 28% of contractions are identified by the patient. The authors conclude that the tracings produced by the TOKOS system are more reliable than maternal perception of uterine contractions.