What TOCO Stands For in Continuous Fetal and Maternal Monitoring
TOCO stands for tocodynamometry (or tocodynamometer), which is a device that measures and records uterine contractions during labor through an external pressure transducer placed on the maternal abdomen. 1
Technical Definition and Function
Tocodynamometry is the standard method for monitoring uterine activity during labor, measuring the amplitude and frequency of contractions through external monitoring technology 1
The electronic fetal monitor uses either an external pressure transducer (the tocodynamometer/TOCO) or an intrauterine pressure catheter (IUPC) to assess contractions 1
TOCO provides information about contraction frequency and approximate duration, but cannot accurately measure the actual strength or intensity of contractions—this requires an IUPC if precise pressure measurement is needed 1
Clinical Application in Labor Monitoring
In the DR C BRAVADO mnemonic used for interpreting continuous electronic fetal monitoring, the "C" stands for Contractions, which are assessed for rate, rhythm, frequency, duration, intensity, and resting tone using tocodynamometry 1
Contractions are classified as normal (no more than five contractions in a 10-minute period) or tachysystole (more than five contractions in a 10-minute period, averaged over a 30-minute window) based on TOCO readings 1
The term "hyperstimulation" is no longer accepted terminology and should be replaced with "tachysystole" 1
Limitations and Alternatives
TOCO suffers from frequent signal dropout requiring repositioning by nursing staff, and may fail completely in obese patients 2
Research shows that TOCO does not correlate well with the gold-standard IUPC, with a Contractions Consistency Index of only 0.69 ± 0.27 compared to 0.88 ± 0.17 for newer electrohysterography (EHG) technology 2
TOCO performance is significantly affected by maternal obesity, unlike newer monitoring technologies 2
For home uterine activity monitoring (HUAM), tocodynamometry combined with daily telephone calls was studied but found ineffective for preventing preterm birth and is not recommended 1