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Poster Session 3

Category: Labor

Poster Session 3

(727) Variation in Sink Water Temperature for Perineal Warm Compresses During Labor

Thursday, February 12, 2026

10:30 AM - 12:00 PM

Submitting Author and Presenting Author(s)

Anna E. Riegger, BS (she/her/hers)

Medical Student
University of Michigan
Ann Arbor, Michigan, United States

Coauthor(s)

MM

Mariana Masteling, PhD

University of Michigan
Ann Arbor, Michigan, United States
JE

Julia Erickson, BS

Clinical Research Coordinator
University of Michigan
University of Michigan, Michigan, United States
Jourdan E. Triebwasser, MA, MD (she/her/hers)

Clinical Associate Professor
University of Michigan
Ann Arbor, Michigan, United States
Christopher X. Hong, MD (he/him/his)

Assistant Professor, Urogynecology and Reconstructive Pelvic Surgery
University of Michigan
Ann Arbor, Michigan, United States

Objective:
Perineal warm compresses during labor reduce the risk of obstetric anal sphincter injuries, yet clinical practice often deviates from standardized protocols. While prior studies used bedside water baths heated to ≥45°C, real-world application typically involves warming washcloths using sink water, which may be inconsistent. This study aimed to characterize the maximum sink water temperature in labor rooms, time to reach maximum temperature, and variation across rooms to identify gaps in current practice and inform device design for standardization.

Study Design:
We conducted a prospective observational study of 30 labor rooms within a tertiary obstetric hospital, each with an in-room sink routinely used to prepare warm compresses. After a cold water washout, the hot water faucet was opened at maximal flow. Real-time faucet water temperature was measured using a thermal camera (FLIR E54) until stabilization (Figure 1). Time–temperature profiles were analyzed to determine maximum steady-state temperature (< 1% further change), time to maximum temperature, and time to ≥45°C. Water volume was calculated using manufacturer-reported flow rate.

Results:
Significant variation in time–temperature profiles was observed across the 30 rooms (Figure 2). The median maximum steady-state water temperature was 45.4°C (IQR 44.6 - 46.2), which required a median of 77 seconds to reach (IQR 66–84). Of the 30 rooms, 19 reached a maximum steady-state temperature of ≥45°C, requiring a median of 62 seconds (IQR 51–73). Based on the time to reach either 45°C or steady-state temperature, the median volume of water used was estimated at 5.8 - 7.3 liters, respectively.

Conclusion:
While most rooms reached the 45°C threshold, substantial variability in time to temperature was observed. More than one minute of continuous flow was typically required, posing practical limitations in clinical settings. These findings highlight the need for accessible, consistent heat sources to enable standardized implementation of this evidence-based practice.