Uterine Activity (Tachysystole and Montevideo Units)
Averages contractions over three 10-minute windows to call tachysystole, more than 5 per 10 minutes as ACOG defines it.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Contractions, first 10 minutes
- 6
- Contractions, second 10 minutes
- 6
- Contractions, third 10 minutes
- 5
Result: 5.7 contractions per 10 minutes averaged over 30 minutes: tachysystole (more than 5).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Contractions, first 10 minutes
- Contractions, second 10 minutes
- Contractions, third 10 minutes
- Contractions in one 10-minute window (for Montevideo units)
- Average peak pressure
- Baseline tone
How this is calculated
Citation
Frey HA, Tuuli MG, Roehl KA, et al. Can contraction patterns predict neonatal outcomes? J Matern Fetal Neonatal Med. 2014;27(14):1422-1427. Spong CY et al. Preventing the first cesarean delivery. Obstet Gynecol. 2012;120(5):1181-1193. Read the sources: Frey 2014 ↗, Spong 2012 ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.