If you have elastic tissue, finding the right pump flange size can feel confusing and frustrating. Maybe your nipple looks normal at rest, but once the pump turns on, everything stretches and nothing seems to fit right.

This is something I’ve seen so often with the families I’ve worked with—and if that sounds familiar, the video above walks you through it step by step. If you prefer to read instead of watch, keep scrolling.

I’m so glad you found your way here.

Why Elastic Tissue Changes Fit

Elastic tissue can make pump fitting a little trickier, but it doesn't mean you can't find a comfortable, effective fit. You may just need to experiment a little more to figure out how your tissue behaves once the pump turns on.

The biggest difference is that elastic tissue stretches more under suction.

With firmer tissue, the nipple usually stretches forward a little when the pump applies suction. Its shape changes, but the diameter may stay fairly close to what it was before pumping.

With very elastic tissue, the nipple can stretch much farther into the flange tunnel. And as it gets longer, it can also become narrower.

That means the nipple diameter you measure at rest may not be the diameter you actually have while pumping.

This is one reason someone with elastic nipples can carefully measure, choose the flange size that seems correct, and still end up with a flange that feels too big once they start pumping.

Elastic tissue doesn't change the basic goal of pump fitting. You still want your nipple to move freely through the flange tunnel while keeping as much of the surrounding areola outside of it as possible. You just have to account for the fact that your nipple may change shape more dramatically under suction.

How to Size and Fit Your Flange

Start With Your Measurement

Your nipple measurement is still a useful place to start. But think of that number as the beginning of the fitting process rather than a guarantee that one particular flange will be perfect.

If you're not sure how to measure or how to build a few sizes to test, I walk through that process in my Breast Pump Flange Sizing Guide.

Then Try Sizing Down

Because elastic nipples can become narrower as they stretch, you may find that a flange one or two millimeters smaller than your resting measurement actually works better while you're pumping.

So if you're putting together a fit kit, include your measured size and a couple of smaller sizes rather than only testing the number you measured.

You're looking for the size that lets your nipple stretch and move comfortably without pulling a lot of your areola into the flange with it.

The best fit isn't necessarily the flange that matches the number on your ruler perfectly. It's the one that works with your anatomy while you're actually pumping.

Silicone Inserts, Lubrication & Shape

Why Silicone Inserts Help

One of my favorite tools for people with elastic tissue is a silicone flange insert.

These inserts fit inside a standard pump flange and make the tunnel smaller, so you can get much closer to the diameter your nipple actually needs.

But the smaller diameter isn't the only reason they can work so well for elastic nipples.

As the opening gets smaller, the usable tunnel also becomes shorter. That can be helpful if your nipple becomes very long under suction, because an extremely stretchy nipple can sometimes reach the back of a longer flange tunnel and become uncomfortable.

Silicone inserts also have a little grip to them. That slight stickiness can help the areola stay outside the tunnel while the nipple moves through the center opening.

That's exactly what we want: your nipple moving through the flange, without the surrounding tissue following it inside.

Keep the Outside Grippy

The tricky part is that you want two different things happening at the same time.

You want the outside of the silicone insert to stay a little grippy so the surrounding tissue doesn't slide inward. But you want the inside of the tunnel to be slippery enough that your nipple can glide back and forth comfortably.

So instead of coating the whole flange, put just a tiny amount of lubricant inside the tunnel.

A small dental sponge or swab can make this easier because you can place the lubricant exactly where you want it without covering the outside of the insert.

You can use a small amount of a food-safe, water-based lubricant or a nipple ointment you already use. If you're using silicone parts, check the manufacturer's instructions for what products are appropriate for that material.

Full Silicone Flanges

You may also see complete silicone pumping flanges marketed for elastic tissue. Some people really like them because the silicone itself can grip the breast or chest tissue.

What I don't love about some of these designs is that the sizing may be less specific. Instead of having a clearly defined tunnel diameter, some gradually narrow from a wide opening into the tunnel.

Your anatomy doesn't gradually taper like a traffic cone. Your breast or chest is wider, and then there is a much more distinct transition to the nipple.

For that reason, I often prefer a flange with a clearly sized tunnel and a silicone insert that lets you get very specific about nipple diameter.

Flange Shape Matters Too

Diameter isn't the only part of pump fit. The shape of the flange where it sits against your breast or chest matters too.

Traditional pump flanges often look a little like traffic cones. But bodies aren't shaped like traffic cones.

If you have a rounder breast or chest, a crater-shaped flange may sit more naturally against your body and create a better seal.

So for some people with elastic tissue, the best combination is a flange shape that matches the body well, plus an insert that gives the nipple the right tunnel diameter.

What If Pumping Still Hurts?

Don't Automatically Turn Up the Suction

If you're struggling to remove milk, it can be tempting to keep turning the suction higher and higher.

But needing the pump at maximum suction just to get it to work can be a clue that the flange fit deserves another look.

When your flange fits your nipple well, you should be able to use a comfortable suction level while your nipple moves freely through the tunnel and milk is removed effectively.

More suction isn't automatically better. The goal is not to tolerate the strongest vacuum your pump can create. The goal is to find the combination of fit and suction that works well for your body.

You Don't Need a Special Pump

I also get asked which pump is best for elastic nipples.

The important part isn't necessarily finding a special pump made for elastic tissue. It's getting the flange attached to that pump to work with your anatomy.

A different flange size, silicone insert, lubrication, or different flange shape can often change the pumping experience without changing the pump itself.

Protect Stretchy Tissue

In my clinical experience, very stretchy tissue can also be more delicate and more prone to irritation or damage when it is repeatedly pulled too far into a pump flange.

That makes getting the fit right especially important. If the flange is too large or the suction is too strong, elastic tissue can keep stretching farther into the tunnel instead of the pump simply removing milk more effectively.

The goal isn't to use as much suction as you can tolerate. It's to get the best flange fit you can so you can use the lowest comfortable suction that still removes milk well.

If you have to keep turning the suction higher just to get milk out, take another look at the flange fit before assuming your pump isn't strong enough.

Pumping With Confidence

Elastic tissue doesn't change the basic rules of pump fitting. Your nipple still needs enough room to stretch and move, your areola should stay mostly outside the tunnel, pumping should be comfortable, and the pump should remove milk effectively.

You may simply need a few modifications to make those rules work with your body.

That might mean trying a slightly smaller flange, adding a silicone insert, lubricating only the inside of the tunnel, or using a flange shape that fits your breast or chest more naturally.

And if you only pump occasionally, having a perfectly exact fit may not make a huge difference in the big picture. You aren't "pumping wrong" because every millimeter isn't perfect.

But if pumping is a major part of your feeding plan, small changes in comfort and efficiency can add up when you're doing this several times every single day.

Getting the fit right means all of that time and effort has a better chance of working for you.

You're worth it.