Why Is My Breast Milk Foamy When Pumping?

tips to increase breastmilk

Every pumping mom works hard to provide nutritious breast milk for their growing infant, but sometimes pumping can get confusing.  Often with my first child, I used to wonder why is my breast milk foamy when pumping.

If you have ever pumped, then you have probably noticed lots of bubbles in the milk.

Many new moms who haven’t experienced this before are quick to throw out the foamy milk thinking it will harm their baby.

First-time moms assume that the milk is bubbly because of soap residue that they may have left in the pump while rinsing it.

Even with a squeaky clean and well-sanitized pump, it’s possible to notice bubbles while pumping breast milk.

Let’s look at why your breast milk may be foamy while pumping.

Pumping breastmilk

Why Is My Breast Milk Bubbly When Pumping?

Over Supply and Fast Letdown

When your breast is heavy and full, you’ll experience a forceful flow while pumping.

The reason behind the fast letdown is because there’s a lot of milk coming out.

Usually, this happens in the morning, during your first pumping session of the day, or if you’ve waited a couple of hours between pumping sessions.

A woman’s nipple typically has between 15 and 20 milk duct orifices through which the milk comes out.

When a lot of milk is forcefully coming out of all these holes simultaneously, the pressure will make the breast milk bubbly while pumping.

Loose Pump Connection

Sometimes your breast milk will appear foamy because your pump has a loose connection with some parts not fitting right.

This will affect the suction process and introduce air into the pump. Your milk may fail to drop into the bottle and will instead cause bubbles in flange while pumping.

Check the flange to make sure it’s completely flat, as when it’s not, it causes bubbles.

Several popular pumps have a white membrane cap, a soft piece of rubber that creates suction. Confirm that it is tightly snapped before you start pumping.

You may have to disassemble all the parts and use that specific breast pump manual to reassemble them again.

This will ensure that components are well-connected. Alternatively, if any of the parts is faulty, you’ll need to replace them or buy a whole new pump.

Chemical Composition

The chemical composition of breast milk will make it foamy when pumping. It’s merely a natural property of human milk.

Breast milk is composed of protein and other components that cause bubbles when there’s a considerable amount of pressure applied to it.

Just like when you shake a bottle with breast milk, and it gets bubbly, when you’re pumping it, the force and suction are likely to cause foamy milk because of its natural properties.

foamy breastmilk

Will Foamy Milk Affect Your Baby?

Although foamy milk is not dangerous, it has a few downsides. When your baby drinks it, they will get gassy.

If you’ve fed your baby foamy milk before, you’ve most likely noticed that they get fussy or spit out a lot.

Also, they may end up with frequent and frothy poop.

In addition to the lactose content in the foremilk which causes gas, the bubbles will also cause discomfort and sometimes pain in the baby’s tummy.

Their intestinal tract is still immature, and they don’t handle gas well.

Make sure to burp your baby frequently to remove any gas caused by the bubbly milk.

If the milk is specifically for storage in the freezer, make sure you don’t have any bubbles as it can cause freezer burn.

Freezer burn happens when frozen breast milk is damaged by oxidation and dehydration because of the air bubbles.

The milk loses its moisture and will not hydrate your baby properly.

It will also alter the taste of the milk, causing your baby to reject the thawed milk. If you’re storing the milk for a short time, say a few weeks, freezer burn will not happen.

However, if it stays in the freezer for a long time, anything six months and up, you will experience freezer burn.

Frozen Breastmilk

How Do You Remove Foam or Bubbles From Pumped Milk?

Before you pump, if you notice that your breast is full and likely to have a forceful flow, start by expressing in the sink with your hands for a bit.

Don’t overdo it because you’ll prompt even more milk. When you realize that the flow is less forceful, then go on to use the breast pump.

After pumping, whether the milk is in a storage bag or bottle, set it aside for a few minutes before keeping it in the refrigerator or feeding your baby.

Some of the bubbles will disappear. Storage bags are highly recommended for long term storage because you can easily remove the air bubbles after pumping.

Pump it in a container first before transferring it to the storage bag as holding the bag upright may be a challenge.

Pour the milk through a flange, which acts as a funnel into the bag to avoid spilling. Use the scissors technique to eliminate as many air bubbles as possible.

When transferring breast milk from the bottle, ensure you get off all the fat from the sides into the storage bag.

Starting where the breast milk stops in the bag or where the air bubbles are, squeeze your index and middle fingers around the bag like a pair of scissors.

Move upward on one side of the bag removing any bubbles and excess air. Zip that side of the bag.

Start squeezing the other side until all the air is out, then seal completely. Ensure that you run your fingers over the zipper several times to ensure that it’s secure.


If you ever been worried and wondered, why is my breast milk foamy when pumping? We hope you now have the answers you need.

Also, now you know what to do about it. Although in most cases, soap is not the cause of bubbles in breast milk when pumping, it’s wise always to double-check.

Before pumping, make sure your breast pump is well rinsed to rule that out. The tiniest amount of soap in breast milk can be harmful to your baby.

However, bubbly latte-like breast milk is healthy, so don’t pour it down the drain.


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