SMFM Special Statement · Updated 2026

Reducing infection transmission during ultrasound

A practical workflow for MFM physicians and ultrasound technologists.

Chukwuma Onyeije, MD · Maternal-Fetal Medicine

OpenMFM Presentation Standard v1.0Evidence review: Aug 31, 2026

Why this matters

Every examination is an infection-control decision

Pathogens are microscopic. The safety system cannot depend on seeing contamination.

Invisible

Clinically significant bacteria and viruses can persist on transducers and equipment.

Designed

Correct classification, barriers, gel, cleaning, and processing reduce transmission risk.

Design the
safe workflow

Learning objectives

Classify. Prepare. Process. Verify.

Classify the contact route

Noncritical, semicritical, or critical.

Select the full barrier bundle

Hand hygiene, gloves, cover, and gel.

Process at the required level

Clean first, then disinfect or sterilize.

Build a verifiable unit system

Train, document, store, audit, and improve.

Spaulding classification

The tissue the probe touches determines the processing level

Noncritical

Intact skin

Routine transabdominal ultrasound.

Clean + low-level disinfect

Semicritical

Mucosa or nonintact skin

Vaginal probes; abdominal probes used on nonintact skin.

Clean + high-level disinfect

Critical

Sterile tissue or vascular system

Intraoperative transducers and devices entering sterile sites.

Clean + sterilize

If sterilization is not compatible with the transducer:SMFM identifies high-level disinfection as the only reasonable alternative.

Procedure route map

One route map prevents most errors

External

Skin contact

Hand hygiene

Gloves by skin condition

Cover and gel by skin condition

Clean + low-level disinfect in Figure 1

Percutaneous

Needle or catheter

Hand hygiene

Sterile gloves

Sterile cover

Sterile single-use gel

Clean + low-level disinfect after external guidance

Internal

Mucosa or operative field

Hand hygiene

Nonsterile or sterile gloves by use

Viral-barrier or sterile cover

Appropriate gel

Clean + high-level disinfect; package for storage

Correct sequence

Cleaning must happen before disinfection

Remove coverContain

→

Remove gelClean

→

Inspect surfaceVerify

→

Apply required processDisinfect / sterilize

Debris blocks agent contact

Cleaning is not optional

Visible gel and other material must be removed. Then use water with detergent, an enzymatic product, or a compatible wipe according to manufacturer instructions.

A disinfectant cannot work through residual material.

External ultrasound

External examinations still require a deliberate plan

Intact, clean skin

Hand hygiene

Gloves at operator discretion

No cover

Nonsterile gel

After: clean + low-level disinfect

Contaminated skin

Hand hygiene

Nonsterile gloves

Single-use cover

Nonsterile gel

After: clean + low-level disinfect

Nonintact skin

Hand hygiene

Nonsterile gloves

Single-use cover

Sterile gel

Figure 1: clean + low-level disinfect

Resolve locally:SMFM Table 1 calls an abdominal probe used on nonintact skin semicritical and specifies high-level disinfection, while Figure 1 shows low-level disinfection after a cover. Align local policy with infection prevention, current AIUM guidance, and the transducer manufacturer.

Ultrasound-guided procedures

Percutaneous procedures require sterile barriers and sterile gel

Amniocentesis

Transabdominal CVS

Umbilical blood sampling

Intrauterine transfusion

Fetoscopy with external guidance

Other needle/catheter procedures

The bundle

Hand hygiene · sterile gloves · sterile transducer cover · sterile gel from a single-use packet · strict aseptic technique.

“Bacteriostatic” and “preservative” do not mean sterile. The package must specifically say sterile.

Internal-use transducers

Internal probes require high-level disinfection after every patient

Hand hygiene

→

Nonsterile gloves

→

Viral-barrier cover

→

Sterile or bacteriostatic gel

→

Remove gel + clean

→

High-level disinfect probe + handle

→

Package for storage

Low-level disinfection is insufficient

Pathogenic organisms can survive low-level processing of transvaginal transducers.

The cover is an added barrier

It does not change the need to clean and high-level disinfect between patients.

Transducer covers

A cover reduces exposure. It does not replace reprocessing.

8-81%

Leakage reported in older studies of some commercial probe covers.

0-5%

Leakage across 10 commercial brands in a 2020 study of 500 covers.

For intravaginal or intrarectal use, choose a product documented as a viral barrier, not merely a generic cover.

Coupling gel

Gel selection changes with the procedure

Noncritical external exam

Nonsterile gel is acceptable on intact skin. Multiuse containers may be used.

Never refill a multiuse container. Discard it when empty.

Semicritical internal use

Use sterile or bacteriostatic gel from single-use packets inside and outside the cover.

Follow local policy and manufacturer instructions.

Critical or percutaneous use

Use only gel specifically labeled sterile, supplied in a single-use packet.

“Preservative” or “bacteriostatic” alone is nonsterile.

Warmers increase the concern:Multiuse containers can harbor pathogens, especially when kept warm. Even products labeled sterile have been implicated in outbreaks, so remain alert to recalls and safety notices.

High-level disinfection

HPV efficacy matters when selecting a system

HPV

Chlorine dioxideYes

Hydrogen peroxide systemsYes

Hypochlorite / hypochlorous acidYes

Peracetic acidYes

Ultraviolet-C lightYes

Glutaraldehyde or OPA productsVariable

Hydrogen peroxide + peracetic acidUnknown

Match the exact product, concentration, time, temperature, and transducer compatibility. The active ingredient alone is not the complete protocol.

What changed since 2020

The OPA update is nuanced

Newer studies found approximately 4-log to 5-log HPV inactivation. SMFM now states that OPA can be considered for high-level disinfection of vaginal transducers.

Operational constraint

OPA is a volatile organic solvent. Use adequate ventilation to reduce respiratory, eye, and skin irritation. Do not use it in ultrasound rooms or other rooms occupied by patients.

Older concern
limited activity

Updated evidence
4-log reduction

Updated evidence
up to 5-log

Complete processing

Process the handle, then protect the processed probe

Remove

Discard the cover without contaminating clean surfaces.

Clean

Remove gel and visible material from probe and handle.

Process

Disinfect the transducer and handle at the required level.

Dry / verify

Complete the manufacturer's cycle and handling instructions.

Protect

Store in a clean or sterile single-use sleeve; date it as good practice.

The handle is part of the contaminated device

High-level disinfection that stops at the probe face leaves a preventable gap.

Cycle logging can support traceability

Some automated systems include documentation software. SMFM notes that logging is good practice but not currently mandated by guidelines.

Environmental controls

The transducer is not the only contaminated surface

Keyboard

Cables

Connectors

Gel warmer

Patient bed

Control panel

No single
optimal frequency

Evidence does not define one best interval for every surface. Each practice must specify what is cleaned, by whom, with what compatible product, and how often.

Do not improvise compatibility

Quaternary ammonium products may be suitable for much equipment, but check manufacturer documentation before use.

Hand hygiene and gloves

Hand hygiene and gloves are separate safeguards

Contact route	Hand hygiene	Gloves	Key point
Intact skin	Before and after patient contact	Operator discretion	Clean + low-level disinfect the probe
Semicritical use	Before and after patient contact	Nonsterile gloves	Cover + required gel + high-level disinfection for internal use
Critical use	Before and after patient contact	Sterile gloves	Strict aseptic technique; sterile cover and gel

Gloves are not 100% leak-proof

Hand hygiene remains mandatory whether gloves are used or not.

Make hygiene visible

Performing hand hygiene in the patient's view can reinforce trust and safety.

Safety culture

A safe unit is designed by leadership

Leadership owns
the system

Assign accountable ownership

Designate oversight, but keep ultimate responsibility with practice leadership.

Provide space, time, and supplies

A protocol fails when the physical workflow makes compliance unrealistic.

Train and supervise

Teach the rationale, the product instructions, and the exact local process.

Document and audit

Monitor adherence, investigate failures, and close the feedback loop.

Protect the culture

Do not normalize shortcuts because no transmission event is visible.

Apply the framework

Rapid scenarios: choose the complete bundle

Scenario 1

Routine anatomy scan on intact abdominal skin

Answer: hand hygiene; gloves optional; no cover; nonsterile gel; remove gel, clean, and low-level disinfect.

Scenario 2

Transvaginal cervical length

Answer: hand hygiene; nonsterile gloves; viral-barrier cover; sterile or bacteriostatic single-use gel; clean and high-level disinfect probe and handle; sleeve for storage.

Scenario 3

Amniocentesis under external ultrasound guidance

Answer: hand hygiene; sterile gloves; sterile cover; sterile single-use gel; clean and low-level disinfect after the procedure.

Scenario 4

Abdominal imaging over a draining surgical wound

Answer: hand hygiene; nonsterile gloves; single-use cover; sterile gel. Confirm the post-exam disinfection level in local policy because SMFM Table 1 and Figure 1 differ.

Implementation tool

A one-page unit protocol aligns the team

Before contact

Classify the planned examination.
Confirm patient latex allergy.
Select gloves, cover, and gel.
Verify supplies and processing capacity.

After contact

Remove and discard single-use items.
Remove gel and visible debris.
Clean probe and handle.
Apply the required processing level.

Before storage

Complete cycle and drying steps.
Inspect the device.
Document when required.
Package in a clean or sterile sleeve.

System controls

Train and competency-check staff.
Define environmental cleaning.
Track recalls and product changes.
Escalate deviations immediately.

The protocol should make the safe action the easy action.

Evidence and controversies

Strong workflow consensus. Important implementation gaps.

What is clear

All probes require cleaning and disinfection between patients.
Internal probes require high-level disinfection.
Percutaneous procedures require sterile single-use gel.
Probe covers do not replace reprocessing.

What needs local resolution

Nonintact-skin discrepancy between Table 1 and Figure 1.
Optimal frequency for cleaning nonprobe equipment.
Whether cycle logging should be mandatory locally.
Product-specific HPV efficacy and compatibility.

What leaders should do

Reconcile policy with infection prevention and current AIUM guidance.
Follow exact manufacturer instructions for use.
Audit the full workflow, not only the final wipe.
Update the protocol when products or guidance change.

Evidence label:The attached SMFM Special Statement is a patient-safety special statement aligned with AIUM, CDC, and FDA guidance. It does not grade individual recommendations using a formal evidence-rating system.

Take-home messages

Clinical pearls

01Classify the contact route before the examination.

02Clean every probe before any disinfection step.

03Internal probes require high-level disinfection.

04A cover is a barrier, not a processing substitute.

05Use viral-barrier covers for internal exams.

06Use sterile single-use gel for percutaneous procedures.

07Process the handle as well as the probe.

08Hand hygiene remains mandatory with gloves.

09Follow exact product and manufacturer instructions.

10Leadership owns the system and its reliability.

References

Core evidence base

1. Society for Maternal-Fetal Medicine. Bauer ST, Combs CA; SMFM Patient Safety and Quality Committee. Reducing the risk of transmitting infection during ultrasound examination - Updated 2026. Pregnancy. 2026;2:e70391. doi:10.1002/pmf2.70391.

2. American Institute of Ultrasound in Medicine. Guidelines for Cleaning and Preparing External- and Internal-Use Ultrasound Transducers and Equipment Between Patients as Well as Safe Handling and Use of Ultrasound Coupling Gel. 2025 revision.

3. CDC, Rutala WA, Weber DJ, HICPAC. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Updated June 2024.

4. US Food and Drug Administration. FDA-Cleared Sterilants and High Level Disinfectants With General Claims for Processing Reusable Medical and Dental Devices. 2023.

5. Joint Commission. Improperly Sterilized or HLD Equipment - A Growing Problem. Updated 2018.

6. Centers for Disease Control and Prevention. Alert: Use Only Sterile Ultrasound Gel for Percutaneous Procedures. Updated May 13, 2025.

7. Casalegno JS, et al. High risk HPV contamination of endocavity vaginal ultrasound probes. PLoS ONE. 2012;7:e48137.

8. M'Zali F, et al. Persistence of microbial contamination on transvaginal ultrasound probes despite low-level disinfection. PLoS ONE. 2014;9:e93368.

9. Basseal JM, Westerway SC, Hyett JA. Integrity of ultrasound probe covers used for transvaginal examinations. Infect Dis Health. 2020;25:77-81.

10. Hudson MJ, et al. Outbreak of Burkholderia stabilis infections associated with contaminated nonsterile, multiuse ultrasound gel. MMWR. 2022;71:1517-1521.

11. Meyers J, et al. Susceptibility of high-risk HPV16 to clinical disinfectants. J Antimicrob Chemother. 2014;69:1546-1550; Meyers C, et al. UVC inactivation of HPV. PLoS ONE. 2017;12:e0187377.

12-14. Ozbun MA, et al. EBioMedicine. 2021;63:103165. Egawa N, et al. EBioMedicine. 2021;63:103177. Ngu A, et al. Infect Control Hosp Epidemiol. 2015;36:581-584.

Educational notice. This presentation supports professional education. It does not replace manufacturer instructions for use, institutional infection-prevention policy, regulatory requirements, or clinical judgment. Evidence reviewed August 31, 2026.