Labor Lensby LlaMamma

Intrauterine Pressure Catheter (IUPC)

A thin, water-filled tube placed through the cervix into the uterus to measure exactly how strong contractions are — used when Pitocin isn't working the way expected or the external toco isn't reading the strength.

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What it is

The external toco measures when contractions happen but not how strong they are. An IUPC gives an actual pressure reading (in mmHg) and calculates 'Montevideo units' — a number the team uses to decide whether contractions are strong enough to be working. Like a scalp electrode, it requires ruptured membranes and enough dilation. It's most often placed during Pitocin inductions where labor isn't progressing despite a maximum dose, or in a labor after cesarean where the team wants precise data.

Evidence review links

Each link opens the full review on the publisher's site in a new tab.

Possible benefits

  • Precise measurement of contraction strength — helps decide whether more Pitocin will help or a cesarean is more appropriate[ACOG↗][ACOG↗]
  • Can prevent an unnecessary cesarean by showing contractions truly aren't strong enough yet[ACOG↗]
  • Some IUPCs can also amnioinfuse (add saline back into the uterus) for variable decelerations or thick meconium[ACOG↗]

Possible risks

  • Small risk of uterine perforation or placental disruption during placement[ACOG↗]
  • Requires ruptured membranes and adequate dilation[ACOG↗]
  • Small increase in intra-amniotic infection when membranes have been ruptured a long time[ACOG↗]

Alternatives

  • Continue with external toco and re-palpate contractions by hand to estimate strength[ACOG↗]
  • Try a longer time with current Pitocin, position change, or a Foley bulb if not yet used[ACOG↗]
  • Proceed to cesarean without IUPC if the clinical picture is already clear[ACOG↗]
Run BRAIN with Labor LensGet Benefits, Risks, Alternatives, Intuition, and Nothing/Wait for Intrauterine Pressure Catheter (IUPC) — plus questions for your care team.

Current evidence

IUPC is a standard tool in ACOG's Safe Prevention of the Primary Cesarean Delivery consensus — many 'labor arrest' cases are diagnosed only after ≥ 4 hours of Pitocin with adequate contractions measured by IUPC (≥ 200 Montevideo units).

Where the evidence is clear · where people may choose differently

For most topics, guidelines from ACOG, WHO, and other major bodies broadly agree on the core safety points (when to act in an emergency, informed-consent standards, monitoring baselines). Where reasonable people — and even guidelines — differ tends to be around thresholds (when to start or stop something), preferences (comfort, environment, support), and values (how you weigh small risks against benefits). Use the questions below to explore those pieces with your care team.

Educational only. Your care team can help you weigh what applies to your specific situation.

Related evidence topics

Questions to ask your care team

  • ?Why an IUPC rather than continuing with external toco?
  • ?How many Montevideo units are we measuring, and what number would change the plan?
  • ?How long will we give this Pitocin dose before deciding next steps?
  • ?Are we also considering amnioinfusion?

Universal questions (works for any decision)

A short BRAIN-style set you can bring to any conversation about interventions, monitoring, or care decisions.

  • ?Why are you recommending this now — is it urgent, routine, or optional?
  • ?What happens if we wait an hour (or longer) before deciding?
  • ?What signs would tell us this is working — or that we need to change course?
  • ?What are the alternatives, including doing nothing?
  • ?What would you recommend if this were your family?
  • ?What would change your recommendation?

Sources & provenance

Tap a source to open the original guideline or review in a new tab.

Plain-language paraphrase. Re-verify before publish.

Last reviewed: 2026-07-03

Further reading — canonical references

Read the source material directly. Each link opens the publisher's own current guidance in a new tab — cross-check what we summarize against what they say.

Educational only. Guidelines evolve — the linked publisher pages will reflect newer guidance than any static snapshot.

Version history — v1.0.0

  • v1.0.0 · 2026-07-03 · LlaMamma editors

    Initial intrauterine pressure catheter topic.

New guidance from ACOG, WHO, Evidence Based Birth, or other listed sources is recorded here and can be updated remotely without a new app release.