Baby Spitting Up Breastmilk But Not Formula

So you’ve made the decision to breastfeed your baby. After all, we not only know it’s better for our baby but we feel that it’s better, too. Then you notice one detail: your baby is spitting up after feeding.

However, it only happens with your breastmilk, not during those feedings when you substitute formula. Why is my baby spitting up breastmilk but not formula? Moms, we’ve all been there. I know it’s so easy to wonder if something is wrong with our milk supply.

Take a breath and relax. I felt the same way. Honestly, I was even a little jealous at times. I would feed our baby and have to deal with the spitting-up almost every time. When my husband would feed her formula from a bottle when my supply was low or I was away, there were no issues. The truth is, it wasn’t the formula or my breast milk. It was simple mechanics.

Why Spitting Up Happens

Spitting up is natural. For babies under three months of age, there is really little need for concern. Almost half of all babies experience some type of spitting up during this period. It’s because during this time the lower esophageal sphincter is not mature. Until that muscle gets strong enough to hold down the stomach contents, spitting up is expected. Naturally, you’ll probably notice it more when her belly is full after a feeding.

This reaction is normal. Our daughter was comfortable after these episodes. She was eating well and gaining weight. Chances are, your baby is just like ours. Happy, content, and eating without issue. As long as your baby is hitting these markers there is no need to worry. If you have a “happy spitter,” all is well.

In the end, it was a matter of our making sure that we kept her upright after each feeding. And don’t forget to burp! Getting that excess air out of the belly will help prevent the food from working its way back up the esophagus.

Go with the Flow

When I took these points into consideration, it was easy to see why our daughter was spitting up as much as she did. Remember earlier when I said it was a matter of mechanics? That is the point to remember.

Our breasts let-down milk at varying rates. Regulating the flow can be difficult. A full belly is more likely to cause episodes of spitting up. Look back on the breastfeeding classes you so eagerly took during your pregnancy. Frequent, smaller feedings are easier to digest. Less food equals less spit up.

It also regulates flow. Breasts that have their milk expressed more often are less likely to have a forceful let-down during feedings. The results are less air in your baby’s belly. These feedings will fill her belly with a reasonable amount of milk, satisfying her hunger. In light of this, she’s less likely to regurgitate part of that feeding.

Compared to the breast, bottles offer baby a more regulated stream of milk. The result is a slower feeding that doesn’t fill the belly too quick. Done right, a bottle feeding is also less likely to introduce excessive amounts of air. The result is what I noticed with our daughter. Less gas, and less spit up. My questions over the quality of my milk supply dwindled when I took these factors into account.

I tested this theory. It worked. Bottle-feedings of my breast milk caused less spit-up than feeding directly from my breasts. With time I learned how to prepare my breasts for feedings by pumping some of my milk. My breastmilk flowed at a slower rate, giving my daughter a feeding that flowed in sync with her sucking. It’s important to make sure she has a proper latch on the breast to keep her from swallowing too much air.

Quality Control

But what if these simple ideas don’t work? While you may be concerned, take a look at your diet first. Are you full-on with the caffeine? You’re not going to like this, but overdoing the morning java could be causing her to spit up. Cut back on your intake and see if this makes a difference.

Consider the role allergies or food sensitivities may play in your baby’s spitting up. Allergies or sensitivities to cow’s milk proteins are more common than thought. Cut out the dairy and see what happens. If you’re noticing that she is spitting up formula too, take note. Many formulas contain dairy.

Lastly, has baby’s diet changed? If you’ve begun introducing solid foods they could be the culprit. Slow down the introduction of cereals until her stomach begins to welcome them without fuss. Keep in mind that thickening milk with cereals can reduce spitting up. Always follow the advice of your pediatrician before making this change.


Spitting up isn’t just about the food supply. It’s also how the food gets to the belly. Find nursing positions that keep your baby upright, such as a sling. Never place her on her back after a feeding. Always get that burp out first. If your little one is like mine, chances are she’s fast asleep soon after a feeding. Avoid the urge to get her into the crib. Instead, hold her upright until you’re confident that her tummy has settled.

You may want to cradle her on the left side during and after a feeding. It’s the “football” carry. Strike up the pose with your partner for a chuckle! All laughing aside, this position seems to work best in preventing spit up.

Is it Reflux?

Our babies get reflux too. And it’s uncomfortable for them as well. If your baby is uncomfortable, isn’t gaining weight, or fusses over eating, it could be reflux. There are plenty of medications and (like us adults) lifestyle changes that can make feedings more pleasant and relieve her symptoms.

For the most part, finding a solution to spitting up is simple trial and error. It’s not your milk and it’s not the formula. It’s all about you and baby making feeding time your time.

You might also like this recent article: How to Get Baby to Sleep Without a Bottle and When to Start Weaning Baby Off Formula

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