What TOCO Stands For
TOCO stands for tocodynamometer, a device used to monitor uterine contractions during pregnancy and labor by measuring external tension of the abdominal wall. 1
Device Function and Technology
The tocodynamometer is a strain gauge-based technology that provides information about:
- Contraction frequency 2
- Approximate duration of labor contractions 2
- External tension of the abdominal wall during uterine activity 3
The device works by placing a sensor on the maternal abdomen to detect changes in abdominal wall tension that correspond to uterine contractions. 3
Clinical Context and Limitations
Primary Use
- Routinely used at late stages of pregnancy to predict the onset of labor 4
- Provides telemetric recordings of uterine contractions when used in home uterine activity monitoring (HUAM) systems 1
Important Limitations to Consider
The tocodynamometer has several well-documented shortcomings:
- Frequent signal dropout requiring repositioning by nursing staff 2
- May fail completely in obese patients 2, 5
- Does not provide information on contraction synchrony or coherence, which are important contributors to successful delivery 4
- Misses many contractions compared to gold-standard intrauterine pressure catheters (IUPC) - detecting an average of only 26.4 contractions versus 59.8 for IUPC 5
- Receives poor quality ratings from clinicians with a mean interpretability score of 0.80 out of 2.0 5
Performance Comparison
When compared to the gold-standard IUPC, TOCO demonstrates significantly inferior performance with a Contractions Consistency Index of 0.69 ± 0.27 2. Alternative technologies like electrohysterography (EHG) show superior performance (CCI of 0.88 ± 0.17) and are not affected by maternal obesity. 2