Expressing

• Start by measuring the diameter of your nipple at the base, not including the areola. You can use a ruler, measuring tape or the included size guide for accuracy. This measurement will help you select a flange that allows your nipple to move freely in the tunnel without rubbing against the sides. 
• When trying a flange, your areola should not be pulled excessively into the tunnel -most of the suction should target the nipple itself. If you experience pain, bruising, or notice that milk isn’t flowing efficiently, it may indicate that you need a different flange size. 
• Nipple size can change over time, especially in the early weeks of lactation, so it’s a good idea to check the fit periodically and adjust as needed. Using the correct flange size can make pumping more comfortable and help you maintain a good milk supply. 

Comfort and efficiency when using a breast pump depends on having the correct flange size. The flange is the cone-shaped part that fits over your nipple and areola, and choosing the right size helps prevent nipple pain, bruising and helps ensure that your breast milk flows efficiently.  

No two nipples are the same, and we're here to help you use the correct-sized horn or insert for you.  

Why flange size matters 

The correct flange allows your nipple to move freely in the tunnel without rubbing against the sides, while the areola remains mostly outside.  

If the flange is too small, your nipple may feel pinched, causing discomfort or even tissue damage. If it’s too large, the suction may be weak, reducing milk expression and making pumping less effective. 

Too small: All your nipple rubs against the tunnel and none of your areola gets pulled in. 

Too big: More of your areola is sucked into the horn and may rub against the edge of the tunnel. 

Just right: While you pump, only a small amount of your areola is pulled into the tunnel, not too much or none. Your nipple should move freely in the flange tunnel without excessive friction. 

The impact on milk production 

An ill-fitting flange can affect milk output over time. If suction is uneven or uncomfortable, your breasts may not be stimulated effectively, which can reduce milk removal and potentially impact your supply. Correct flange sizing ensures that milk is expressed efficiently while keeping pumping sessions comfortable, helping you maintain a consistent breast milk supply. 

What is a flange or breast pump horn? 

The horn/flange of your breast pump is the funnel-shaped plastic part that fits over your nipple as you pump. It's also sometimes called a flange or shield.  

What is a breast pump horn insert?  

A breast pump horn insert is a removable liner that sits inside the pump’s flange (the funnel-shaped part that goes around your nipple). Its job is simple: to refine the fit for a personalised pumping experience.  

Some nipples need a narrower space to move comfortably during pumping. An insert reduces the internal diameter so the pump can work more efficiently, with less rubbing and more comfort.  

Tommee Tippee breast pumps have a 24mm horn, and also come with 13mm, 15mm, 17mm, 19mm and 21mm horn inserts so you can personalise your pumping experience. 

Express using the 24mm horn on its own, or add one of the 5 inserts to adapt the size to fit your body. Think of it as a small adjustment that can make a big difference.   

Why do I need to measure my nipples? 

Measuring your nipples and making sure that you're using the right horn size means that every pumping session is as comfortable, efficient, and effective as possible.   

• If your horn is too loose, you'll find it difficult to pump all the milk from your breasts, which may harm your milk supply or make pumping unnecessarily painful. You don't want your nipples to pinch, rub or cause you any discomfort while you pump. 
• If the horn you're using is too tight, your breasts can be constricted in ways that may lead to clogged milk ducts. 

How to measure your nipple and required horn or insert size 

The correct fit is based on how your nipple fits into the tunnel of the horn, rather than how your breast fits into the cone of the horn. 

1. Before you get started, it's best to make sure that your nipple is full size. You can do this by gently rolling it between your thumb and finger or by putting something cold on it. 
2. Roll your nipple between your thumb and finger or put something cool on it to make sure it's full size. 
3. Use the included guide to measure the base of your nipple in millimeters. Only measure your nipple on its own, don't include your areola. 
4. Once you've measured one nipple, repeat the process with the other.  
5. Then, choose the horn insert that's closest to your nipple size.  
6. Once you've measured one nipple, repeat the process with the other. 

Finding your fit isn't an exact science.  

Try starting with the horn or insert size closest to your nipple measurement. And consider trying the next size up or down, too.   

Your pump shouldn't pinch, rub or cause any discomfort.   

You've found your ‘sweet spot’ when you experience the most comfortable and consistent breast milk flow. 

Your nipple size (and the right horn or insert size for you) may change throughout your expressing journey. Keep checking how your pump fits and feels, and adjust the horn size you use accordingly.