When Should You Change Bottle Nipple Flow?

Before I had a baby, I had no idea bottle nipples even came in different flow rates. Bottles were bottles. Nipples were nipples. Then I became a mom and realized there was an entire progression of nipple sizes, and somehow I was supposed to know when my baby was ready to move from one to the next.

After bottle feeding two babies, I have learned that changing bottle nipple flow is much less about following the age printed on the package and much more about watching your baby. Both of my babies started on slower flow nipples, but for very different reasons.

My first started with a Dr. Brown’s Preemie nipple because my doula recommended the slower flow while I was planning to breastfeed and pump. My second was premature and started with a Dr. Brown’s Ultra Preemie nipple in the NICU. From there, I learned to look for feeding cues rather than automatically moving up a nipple size at a certain age.

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How Do You Know When to Change Bottle Nipple Flow?

For me, the biggest sign that it might be time to move up a nipple flow was when feeding suddenly seemed like a lot more work. My baby might be sucking quickly and working hard but not getting milk as efficiently as before.

A bottle that previously went pretty smoothly would start taking much longer, or my baby would seem frustrated while eating. Once my babies were using Level 1 or Level 2 nipples, their bottles generally took around 15 minutes. If a bottle started stretching toward 30 minutes or longer, that was a sign for me to pay attention to what was happening and consider whether the nipple flow might be too slow.

I never changed nipple sizes based solely on age. I watched how my baby was eating first and then looked at the different nipple sizes when I suspected it might be time for a change.

Signs Your Bottle Nipple Flow May Be Too Slow

Every baby is different, but the biggest things I noticed were feeds suddenly taking much longer, my baby sucking very quickly or working noticeably harder to get milk, and frustration during the bottle. Sometimes it was simply that a feeding that had previously felt easy suddenly seemed much less efficient.

The change was not always dramatic. Sometimes I would just notice that my baby seemed to be doing a lot of sucking without getting milk as quickly as before. That was usually when I would start wondering whether it was time to try the next nipple size.

Signs Your Bottle Nipple Flow May Be Too Fast

Moving up is not always the answer. I learned this firsthand when I moved my second baby from a Level 1 to a Level 2 nipple and daycare eventually suggested that I move her back down.

She was spitting up much more than usual, and it was not just the normal small amount of spit up I was used to seeing after bottles. There were times when it was much more forceful. I also noticed things like coughing and gulping when the flow seemed too fast.

That experience was a good reminder that moving to a higher nipple flow is not a milestone you need to reach. If your baby seems more comfortable with the slower flow, there is no reason to rush to the next size just because the packaging suggests it for their age.

Do Not Rely Only on the Age on the Package

Bottle nipple manufacturers often associate their nipple flows with different ages, which can be helpful as a general reference. I just never treated those ages as a schedule I needed to follow.

Instead, I waited until I noticed something changing during feeds. If bottles were taking much longer, my baby seemed frustrated, or I could tell they were working really hard to drink, I would start wondering whether it was time to move up.

If I tried the next nipple and saw coughing, gulping, or significantly more spit up, that told me we might not be ready yet. Your baby’s feeding cues matter more than reaching a certain month on the calendar.

There Are Nipple Sizes Between Preemie and Level 1

This is something I did not even remember until I looked back at my bottle nipple orders. With my premature baby, we started with the Dr. Brown’s Ultra Preemie nipple because that was what she used in the NICU. We later moved to the Preemie nipple and then used the Transition nipple before moving to Level 1.

I think the Transition nipple is particularly helpful to know about because you do not necessarily have to make a big jump from a very slow Preemie flow directly to Level 1. I had completely forgotten we used it until I looked back at what I had ordered.

With my first baby, we started with the Preemie nipple and eventually worked our way through the different flows all the way to Level 4. The progression looked different with each baby, which is another reason I do not think there is one perfect nipple schedule to follow.

How I Test a New Bottle Nipple Flow

When I think it might be time to move up, I do not immediately change every nipple we own. I start by trying the new flow for one daytime bottle when I can actually pay attention to how the feeding is going.

I would not personally experiment with a new flow for the first time during a middle of the night feeding when everyone is tired and I am just trying to get the baby fed and back to sleep. During the daytime, I can watch how quickly my baby is drinking and whether there is coughing, gulping, pulling away, or significantly more spit up.

If the new flow seems comfortable after trying it, I will eventually swap the nipples across all of our bottles. If it seems too fast, I have no problem going back to the previous size and trying again later.

Daycare Helped Me Know When to Change Nipple Sizes

If your baby goes to daycare, the teachers can also be a really helpful second set of eyes. Interestingly, I had completely opposite experiences with my two babies.

With my first, daycare eventually came to me and said they thought it was time to try a larger nipple because of what they were seeing during his bottles. With my second, daycare was actually the reason I went backward. They noticed that the Level 2 nipple seemed like too much and suggested going back to Level 1.

They were feeding my babies multiple bottles during the day, so their observations were really useful. It also reinforced something I had already learned. Nipple flow is not a one way race toward the biggest size. Sometimes sizing up is the answer, and sometimes sizing back down is.

Do You Need to Buy Every Bottle Nipple Size Ahead of Time?

I would not stock up on every nipple size before your baby needs them. I prefer to wait until I start wondering whether my baby is ready for the next flow and then order it.

Bottle nipples are easy enough to get quickly, so I do not see a reason to have every possible size sitting in a drawer before you know what your baby will actually need. I also would not buy a huge number of the next size before testing it.

Try the new flow first and see how your baby handles it. Once you are confident that the new nipple works well, then you can replace the nipples across the rest of your bottles.

Nipple flow wasn't the only thing that changed as my babies started drinking more. We also eventually made the switch from 4 oz to 8 oz bottles, although I still found reasons to keep a few smaller bottles around.

Trust Your Baby’s Cues

One of the hardest parts of becoming a mom is realizing how many things you are somehow expected to know without anyone actually teaching you. Bottle nipple flow was one of those things for me.

There is so much outside noise telling you what your baby should be doing at a certain age. After doing this twice, I have learned that so much of parenting comes down to watching the baby in front of you.

You spend an incredible amount of time feeding your baby, and you will start to recognize what a normal bottle looks like for them. When something changes, pay attention. If you suspect the current nipple has become too slow, try the next flow during a daytime feeding when you can closely watch how your baby handles it.

If it seems too fast, go back down. There is no prize for moving up a nipple size. The right flow is simply the one that allows your baby to feed comfortably.

Frequently Asked Questions

How do I know when to size up bottle nipples?

I looked for changes in how my babies were eating rather than relying only on age recommendations. Longer feeds, noticeably harder or faster sucking, and frustration during bottles were signs that made me consider trying the next flow.

What happens if a bottle nipple flow is too slow?

In my experience, bottles started taking much longer and my baby seemed to be working harder to drink. Sometimes there was also frustration during the feeding, especially when they were sucking quickly but not getting milk as efficiently as before.

What happens if a bottle nipple flow is too fast?

Coughing, gulping, and a significant increase in spit up were the biggest signs I noticed. When one of my babies seemed overwhelmed by Level 2, we went back to Level 1 rather than trying to force the transition.

How long should it take a baby to finish a bottle?

This varies by baby, age, feeding needs, and bottle system. In my experience, once my babies were on Level 1 or Level 2 nipples, bottles generally took around 15 minutes. If feeds suddenly started stretching toward 30 minutes or longer, that was one of the cues that made me look at whether the nipple flow was still working well.

Should I change bottle nipple size based on age?

I did not. I used the manufacturer’s age recommendations as a reference, but I primarily followed my babies’ feeding cues. Both of my babies progressed through nipple flows differently, so I never felt like I needed to move up simply because they reached a particular age.

What is a Transition bottle nipple?

Some bottle systems offer an intermediate flow between their Preemie nipple and Level 1 nipple. With my second baby, we used Dr. Brown’s Transition nipple after the Preemie nipple and before moving to Level 1. I liked having that additional step rather than making a bigger jump in flow.

Can you go back down a bottle nipple size?

Yes, and I did. After moving one of my babies from Level 1 to Level 2, we realized the faster flow was not working well and went back to Level 1. Moving up is not permanent, and there is no reason to stay with a faster nipple if your baby seems more comfortable with the previous flow.

Every baby is different, and feeding concerns are worth discussing with your pediatrician or feeding specialist, particularly if your baby was born prematurely, has difficulty coordinating feeds, frequently coughs or chokes while eating, or you are concerned about their intake or growth.