Newborns should start with the slowest flow nipple available for your bottle brand. Most brands label this as “Slow Flow,” “Level 0,” “Level 1,” or “Newborn,” but those labels are surprisingly inconsistent. A nipple marked “Slow Flow” from one brand can deliver milk twice as fast as the same label from another, so understanding what’s actually happening matters more than trusting the packaging.
Why the Slowest Flow Matters
A newborn’s suck-swallow-breathe coordination is still developing. A nipple that delivers milk too quickly can overwhelm them, causing coughing, choking, gulping, or milk spilling from the corners of their mouth. A slow flow nipple gives your baby time to manage each swallow and take breaths between sucks, which is closer to how breastfeeding works.
If you’re combining breastfeeding and bottle feeding, this is especially important. Colorado’s WIC program recommends using a slow flow or size 0 nipple regardless of your baby’s age to better mimic the natural pace of milk from the breast. Sticking with a slower nipple helps prevent your baby from developing a preference for the faster, easier flow of a bottle.
Brand Labels Don’t Mean What You Think
One of the most confusing parts of choosing a nipple is that “Level 1” or “Slow Flow” varies dramatically between brands. Alberta Health Services tested dozens of nipples and measured their actual flow rates in milliliters per minute. The differences are striking.
The Philips Avent Natural First Flow nipple delivers about 0.86 mL per minute, making it one of the slowest on the market. The Dr. Brown’s Newborn (0+ months) nipple flows at 9.21 mL per minute, more than ten times faster. Both are marketed for newborns. Meanwhile, Dr. Brown’s Level 1 (also labeled 0+ months) flows at 13.31 mL per minute, which puts it in the medium range alongside nipples from brands like MAM, Evenflo, and NUK that are also labeled for newborns.
Some nipples labeled “slow” actually flow faster than other brands’ medium options. The Comotomo Slow Flow (0 to 3 months) averages 9.76 mL per minute, while the Tommee Tippee Closer to Nature (0+ months) delivers 15.90 mL per minute. A baby switching between those two brands would have a very different feeding experience, even though both say they’re designed for the same age.
Here’s a quick look at common newborn-labeled nipples ranked by actual flow speed:
- Slowest: Philips Avent Natural First Flow (0.86 mL/min), Philips Avent Natural 0 months+ (2.25 mL/min)
- Slow: Dr. Brown’s Newborn 0+ months (9.21 mL/min), Comotomo Slow Flow 0 to 3 months (9.76 mL/min)
- Medium (despite newborn labeling): MAM Anti-colic 0 months+ (13.83 mL/min), Tommee Tippee Closer to Nature 0+ months (15.90 mL/min)
- Fast (despite newborn labeling): Philips Avent Anti-colic 0 months+ (17.44 mL/min)
This means the brand you choose matters as much as the flow level you select. If your baby seems to struggle with one brand’s “newborn” nipple, trying a genuinely slower option from a different brand can make a real difference.
Premature Babies Need Even Slower Flow
Preemies often have a weaker suck and less developed coordination, so they need nipples that are slower than standard newborn options. Dr. Brown’s makes an UltraPreemie nipple (4.92 mL/min) and a Preemie nipple (7.22 mL/min), both of which flow more slowly than many nipples labeled “newborn” or “slow flow.” Philips Avent’s Natural First Flow, at under 1 mL per minute, is another option that works well for babies who need a very gentle flow. If your baby was born early or has feeding difficulties, starting with one of these extra-slow options gives them the best chance of feeding comfortably.
Signs the Flow Rate Is Wrong
Your baby will tell you whether the nipple flow is right. The key is knowing what to watch for in both directions.
Flow Too Fast
If milk is coming out faster than your baby can handle, you’ll notice coughing or sputtering during feeds, milk dribbling from the corners of their mouth, or your baby pulling away from the bottle frequently. They may also seem tense or stressed while eating, gulping hard to keep up. If you see any of these signs, try a slower nipple.
Flow Too Slow
A nipple that’s too slow creates its own set of problems. According to Nationwide Children’s Hospital, signs your baby is ready for a faster flow include feeds that take noticeably longer than usual, fast sucking with very few swallows (sometimes causing the nipple to collapse inward), and fussiness or frustration during the bottle. Falling asleep mid-feed before finishing is another common sign. Newborn feeds typically take 15 to 30 minutes. If your baby is consistently taking much longer than that and showing frustration, the nipple may be too slow.
When to Move Up a Size
There’s no set age for switching to a faster nipple. Many brands print age ranges on their packaging (0 to 3 months, 3 to 6 months, and so on), but these are rough guidelines, not rules. Some babies stay on a slow flow nipple for months past the suggested range. Others need to move up sooner.
Watch your baby’s behavior rather than the calendar. If feeds are going smoothly, your baby is gaining weight, and they seem content, there’s no reason to change. This is particularly true for breastfed babies who also take a bottle. Keeping them on the slowest flow that still allows a comfortable feed helps maintain that slower, more natural rhythm and reduces the chance they’ll start refusing the breast.
Paced Feeding Makes Any Nipple Work Better
Regardless of which nipple you choose, the way you hold the bottle changes how fast milk flows. Paced feeding means holding your baby in a more upright position and keeping the bottle nearly horizontal rather than tipping it straight down. This forces your baby to actively suck to get milk, rather than having gravity push it into their mouth. You can also pause every few minutes by tilting the bottle down or gently removing it, giving your baby time to register fullness.
Paced feeding effectively slows down any nipple, which is why it’s recommended for breastfed babies taking a bottle. It also helps prevent overfeeding, since babies get a chance to stop when they’re satisfied rather than drinking simply because milk keeps flowing. Never prop a bottle and walk away, as this creates a choking risk and removes any pacing from the feed entirely.