Insulin pumps and CGMs: how these technologies work together

Not every CGM-and-pump setup works the same way. They can work together in a variety of ways including:

Standalone use

Each device (an insulin pump and a CGM) can be worn alone, or they can be worn together but are not communicating. Your pump delivers insulin based on programmed settings; your CGM shows you glucose readings and trends on your phone or receiver. You still make all dosing decisions yourself, but you can use your CGM readings to decide when and how much to bolus. 

Automated insulin delivery systems

Automated insulin delivery (AID) systems consist of three parts that communicate, an insulin pump, a compatible CGM and an algorithm.  The CGM shares glucose readings with the pump throughout the day and night, and the algorithm adjusts how much insulin the pump delivers based on those readings. You still need to bolus for meals, but background management runs around the clock. Omnipod® 5 is one example of an AID system, using sensor glucose data to automatically adjust basal insulin delivery.

Where do most people start?

Choosing which device to start with is an individual choice. Standalone use can be a starting point as it gives people time to get comfortable with each device before adding automation. While this is an individual choice, the American Diabetes Association (ADA) recommends CGM initiation, at diabetes onset and any time after for children, adolescents and adults with diabetes, who are on insulin therapy. The ADA also recommends AID systems as the preferred insulin delivery method, over multiple daily injections, and non-automated insulin pumps in people with type 1 diabetes and adults with type 2 diabetes.¹

For an AID system to do its job, the CGM and pump need to stay in communication. 

How reliable is the wireless connection between a pump and CGM?

Modern AID systems use Bluetooth to communicate between sensor and pump. In everyday use, connectivity is generally reliable, and most people manage full days, workdays, and nights without interruptions. Like any wireless system, signal can occasionally drop if devices are too far apart or if there’s interference. Most people find connectivity to be a non-issue in practice but knowing what to expect and what to do if there is a break in communication is important.  

What to do if your CGM loses connection

If your sensor temporarily loses its connection to the pump, most AID systems enter a safe fallback mode: they continue delivering a baseline rate of insulin rather than stopping entirely, and they alert you to the signal loss. During the gap, you can still deliver a manual bolus. If you have symptoms that don’t match what your CGM was last showing, use a fingerstick to confirm your glucose level.^†  Once the CGM reconnects, automated adjustments resume automatically.

Wearing two devices takes some getting used to. Most people settle into a routine within a few weeks, and for many, the benefits of better glucose management far outweigh the adjustment period.

Can you shower, swim, and exercise with these devices?

Water resistance varies by device, so it’s worth checking the user guide for both your pump and your CGM sensor before swimming or bathing. Many tubed insulin pumps can be temporarily disconnected for water activities; check your pump’s waterproofing rating to know what’s safe.

The Omnipod 5, for example, carries an IP28 waterproof rating for up to 25 feet for 60 minutes^§ and can be worn during showering, swimming, and other water activities. (The Omnipod 5 controller is not waterproof.)

Tips for sleeping with an insulin pump and CGM

Many people wear both devices comfortably throughout the night. A few things that help:

• Choose sensor and infusion site placements that don’t press uncomfortably against the bed when you sleep on your preferred side. 
• Be aware that pressing down on a CGM sensor can occasionally cause inaccurate readings at night. This is known as a “compression low.”  If you get an unexpected low alert, check your glucose levels before treating.
• Keep your phone on the nightstand within Bluetooth range so alerts reach you without the phone being on your body.

How to best manage adhesion, alarms, and supply routines

Adhesion: Having clean, dry skin before applying either device makes a meaningful difference. Oils, lotions, or moisture under the adhesive are the most common reasons for early peeling. Over-patches (thin adhesive films that go over a sensor or pump infusion site) are also available from third-party retailers to add an extra layer of security.

Alarms: Most systems let you customize alert thresholds. If alerts are waking you up for glucose values within a safe range, work with your care team to adjust your targets. This is a normal part of dialing in a new system, not a sign that something is wrong.

Supply routines: Both devices require regular restocking, whether that’s sensors, infusion sets, reservoirs, or system-specific components. Reordering before you run out and maintaining back-up supplies are simple habits that keep your system running without gaps.