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Welcome to Ask the Expert, a new series where I answer real questions from real Babylist users and parents just like you. Who am I? I&#;m Jen LaBracio, Babylist&#;s Gear Editor, a role that perfectly combines my love of (obsessive) research with my love of all things baby gear.

Regardless of how you decide to feed your baby, most parents will use a bottle at some point during their little one&#;s lifetime. But figuring out the world of bottles and which one to choose? That&#;s another undertaking entirely.

There are a few main choices for bottles&#;plastic, glass and silicone&#;but even more choices when it comes to a bottle&#;s size, shape and venting system. And then there&#;s the questions behind bottle sterilizers and warmers (buy or skip?), nipple sizes, anti-colic systems&#;the list goes on.

There&#;s a lot to think about, and a lot of questions to ask. (And we know, because you asked them!) But don&#;t worry, because we&#;ve got an answer to every single one.

Where do I start with baby bottles???

This question made me laugh, because we&#;ve ALL been there at some point (um, many points?) during our parenting lifetime. I&#;ll try to make it as simple as possible.

If you&#;re going to be adding bottles to your registry, or you&#;ve come to this Q&A after planning on exclusively breastfeeding then realizing you also want to add bottles into the mix, I&#;d start by doing a little research.

Our Best Bottles guide is a great intro to all things bottles and outlines our picks for our favorite, most popular bottle choices among both experts and Babylist parents. It also provides a good overview of all things bottles.

Next, hop over to Babylist on the &#;Gram and settle in to watch our Baby Bottles Showdown. We did a live demo comparing five of the most popular bottle brands and talked through the features of each, how they work and how to decide which bottle is the right pick for you.

If you&#;re in the mood for more videos, your next stop should be the Babylist YouTube channel. We&#;ve got a ton of bottle-specific videos here, covering everything from how to choose the best bottle to showdowns between specific brands.

And finally, if you can, talk to your other parent friends or hit up an online parent group and ask, ask, ask. What bottles did they (and their babies, of course) love? Which ones did they not love? Were some easier to clean than others? Did some work better for breastfed babies? Other parents who&#;ve been there, done that are a huge source of useful information if you&#;re a newbie; utilize their knowledge whenever possible.

Once you find YOUR bottle, how many do you recommend having?

I have an answer + a caveat to this question.

If you&#;re planning on exclusively bottle feeding, plan to have around six to 12 bottles on hand. This will allow for having a bottle ready to go whenever you need one while you&#;re washing the others. If you&#;ll only be using bottles occasionally, three or four is probably a good number.

Caveat: try before you buy! Some babies are picky and can be really particular when it comes to what bottle they&#;ll drink from&#;or won&#;t. And you&#;ll want to make sure you&#;re comfortable with cleaning, assembling, storing etc. whatever bottle you choose.

Instead of registering for or ordering a huge gift set of bottles all from the same brand, pick two or three bottles from different brands that you&#;re the most interested in and buy just one of each at first, or try something like the Babylist Bottle Box that features one each of five of our most popular plastic and and silicone bottles, or the Glass Bottle Try-it Bundle if glass bottles are your preference. Take them for a test drive, see what works, then buy more from there.

What are the best bottles for a breastfed baby?

Lots of parents end up feeding their babies through a combination of both breast and bottle, so this is a question that I hear quite a bit from new parents.

For a full breakdown of all things bottles + breastfeeding, including an interview with a lactation consultant, head over to our Best Bottles for Breastfed Babies guide. Here&#;s a quick overview of the key points if you don&#;t have time to read the full article:

Wait until about three and six weeks before introducing a bottle to your breastfed baby.

Mimic the position you&#;d feed your baby in from the breast when you&#;re bottle feeding. Use an upright hold with the bottle parallel to the floor so the milk is coming at them, not down into their mouths. Use a slower-flow nipple and pace the bottle feeding with pauses every few minutes. Remember that there&#;s no one bottle that all breastfed babies will magically take. A few favorites among lactation consultants include Playtex Baby Nurser with Drop-In Liners, Comotomo and the Medela Breastmilk Bottle. Consult the guide mentioned above for a more comprehensive list of breastfeeding-friendly bottles.

Are glass bottles better than plastic?

If you&#;ve read any of my other Ask the Expert articles (no worries, I&#;ll wait), you know that getting into what&#;s best or better can be&#;tricky. Why? Because we&#;re all pretty different, and what&#;s best for one parent may be 100% the wrong chance for another. So let&#;s frame it another way.

No, glass bottles are not &#;better&#; than plastic bottles. What they are, however, is different. So if you&#;re trying to decide between the two, it&#;s helpful to look over the features of each and weigh the pros and cons as they factor into your particular lifestyle and philosophies.

Glass bottles don&#;t absorb colors or odors like plastic (or silicone) bottles can. They&#;re thermal-shock resistant, which means they can go from freezing cold to piping hot without breaking. They can go right into the dishwasher without fear of chemical leaching (more on that here; and note that the jury&#;s still out on potential negative health effects, so no need to get too worried) and they&#;re pretty easy to clean because they have less parts than many other bottles.

Glass bottles are heavy, though. They&#;re trickier for you (and your baby) to hold and they tend to be more expensive than plastic bottles. There are also less options to choose from as they&#;re not as popular as other bottle options.

What about plastic bottles? The most ubiquitous of all bottle materials, plastic bottles are the most affordable option and offer the most selection. They&#;re also lightweight and won&#;t risk breakage when dropped. But there are potential health and safety concerns around plastics as mentioned above (particularly when heated), and many plastic bottles have lots of small parts that can be a pain to clean.

Figuring out which bottle material is the better choice for your family and your baby simply comes down to weighing these pros and cons and deciding what works best for you. There&#;s no right or wrong answer.

Are glass bottles safe? I&#;m looking for an eco-friendly option.

Totally safe! Just don&#;t drop one on your toe.

When do I use what size nipple?

I remember coming across this as a new mom and thinking to myself, &#;What? Nipples come in sizes?&#; Turns out it&#;s not as complicated as it may seem. (Phew.)

Yes, nipples come in sizes. Each size provides a different rate of milk flow. The reasoning behind nipple sizes is that younger babies need a slower flow of milk, while older babies who are bigger and more accustomed to sucking and swallowing can handle milk coming out of a bottle at a faster rate.

Each brand sizes their nipples differently, but the most common options are either slow, medium and fast or a numbered system that can start as low as preemie and then go one through four. (Some brands also offer Y-cut nipple that&#;s designed for thickened milk, formula or cereal.)

In most cases, you&#;ll want to start your newborn off with a slow flow or preemie/level one nipple and move up to a faster nipple size as your baby grows. There&#;s not hard-and-fast rule as to when exactly to make the switch to a faster nipple flow, but in general, you&#;ll want to keep an eye out for these signs that may signal it&#;s time to size up:

• Your baby is taking longer to finish eating
• Becoming fussy while eating
• Falling asleep during feeding

On the flipside, here&#;s what to look for that may indicate the nipple you&#;re using is too fast and you should size down instead:

• Coughing or choking
• Gulping or hard swallowing
• Milk dripping from mouth
• Bottle refusal

Most bottle brands offer their own specific information about how to select a nipple size and guidelines on when to use each particular level, so be sure to check brands&#; websites with any questions.

One other thing to note when it comes to nipple levels. If your baby is primarily breastfed, many lactation consultants recommend starting with a slow flow nipple and sticking with it as long as possible. Your baby has to work a little harder to get milk from a breast as opposed to a bottle. If you use a faster flow nipple with a breastfed baby, you run the risk of them getting used to the easier milk flow&#;and the lesser amount of effort it takes to get milk&#;and they may start to show a strong preference for the bottle over the breast. This can make switching between the two a bit tougher. Not all babies have this issue; some breastfed little ones do just fine with a faster flow nipple. But it is something to keep in mind.

Bottle warmer and sterilizer&#;are these must-haves?

I have strong opinions on this one. Nope and nope. Bottle warmers and sterilizers are definitely not must-haves in my book, and here&#;s why.

A bottle warmer is fine, but you can accomplish the same thing by sticking your bottle in a mug of hot water for a minute or two&#;no extra accessory needed. Save the money, and save the counter space.

Same goes for bottle sterilizers. While it is recommended to sterilize your bottles before the first use, you can do so pretty easily in a pot of boiling water or in a microwave sterilizer bag. Unless your baby is premature or immunocompromised in some way, most pediatricians will tell you that you&#;ll never have to sterilize your bottles again. Which is why a sterilizer is another skip for me.

All that being said, if you think a bottle warmer is going to make your life as a new parent a lot easier, and that you&#;ll want to continue to sterilize your bottles just for peace of mind, then by all means, go for it. You do you! There&#;s certainly nothing wrong or unsafe about either of these items, and if you think they&#;re going to work for you, then I&#;m all for it.

Best bottles for reflux babies?

Infant reflux is something that a lot of parents have to contend with. Even though it&#;s really common and generally not a cause for concern, that doesn&#;t make it any easier on you (or on your laundry), so hang in there!

The most common cause of reflux in an immature digestive system. While there&#;s often not a whole ton you can do about it other than to simply wait for your baby to get older, choosing a bottle that limits the amount of air your little one is swallowing while feeding can sometimes make reflux babies a little less uncomfortable and reduce the amount of spit up, gas, colic and general fussiness.

When choosing a bottle for a reflux-prone baby, you&#;ll want to look for a bottle with a good venting system: the system that channels air away from the milk or formula and allows for good airflow as your baby drinks, reducing the amount of air they&#;re gulping down. Some brands refer to this as a vent or a venting system, while others call it an anti-colic system or anti-colic valve.

Some bottle brands, like Dr. Brown&#;s, have separate, standalone venting systems inside their bottles, while others, like Comotomo or Nuk, have anti-colic valves built right into the bottle&#;s nipple or collar.

These are some of my favorite bottle choices for reflux babies:

If you are looking for more details, kindly visit HEORSHE.

Can I save my bottles for baby #2? What about the nipples?

Great question! There&#;s a lot to be said for used baby gear, especially since buying new is often such a big investment for gear that has a really short lifespan. The short answer is yes to used bottles, but no to used nipples. Here&#;s why and how to make sure you&#;re keeping your baby safe.

Bottles are totally fine to use again for your second baby as long as you keep these things in mind:

• You&#;ll want to make sure there&#;s no damage whatsoever to any part of the bottle and its components. A little discoloration is fine, but keep an eye out for any mold or for any cracks or chips that may compromise the bottle&#;s structural integrity. If you see anything like this, toss it.
• Same goes for bottle components (minus the nipple, which I&#;ll discuss separately). Check over the bottle&#;s collar, any internal venting system, etc. for any imperfections or mold and replace if you see anything funky.
• Be sure the bottle is functioning properly before you go for round two of use. Fill the bottle with water and test for any leaks. Make sure the collar still properly screws onto the top of the bottle and that there&#;s no warping or cracking.
• Sanitize your bottles and all parts before using them the second time around.

Nipples are the one part of your bottle you&#;ll want to replace completely if you&#;re using them the second time around. The good news is that it&#;s easy and inexpensive to purchase nipples separately. Just be sure the nipples you&#;re buying are still compatible with your bottles, and take them for a test drive with your used bottles before using them with your baby for the first time.

I need a bottle that&#;s easy to clean, safer to use and lighter to hold!

The good news here is that all bottles are safe, so you won&#;t have to worry there.

Based on what you&#;re looking for, I&#;d recommend a silicone bottle. My favorites are Comotomo, Boon Nursh and Nanobebe Flexy.

My 8 month old is rejecting the bottle after never having a problem. Help!

This can be so frustrating&#;I feel you!

There are a few things that might be going on here.

• It may be time to move up to a faster nipple flow. While some babies do just fine long-term with a slow flow nipple, others get frustrated with the effort it takes to get milk from a bottle with a slower nipple. Try moving up a level and see if this does the trick.
• Eight months old is prime time for distractions. Your eight-month-old is suddenly very aware of the world around them, and taking ten or fifteen minutes to sit quietly and drink a bottle when there&#;s so much to see and do instead is often a lot to ask of a baby at this age. Try going into a quiet room to feed your baby the next time they need to eat, if possible. Turn down the lights a bit and limit distractions as much as possible. It may take a few tries, but often making the feeding environment pretty boring is helpful for getting a distracted baby to settle down and eat.
• If you can, try having someone other than the usual suspect feed your baby. A partner, caretaker or grandparent may have the magic touch.
• Check in with your pediatrician. Maybe it&#;s time to alter your baby&#;s feeding schedule, offer more/less solid foods or look into some other issue like reflux. Always feel comfortable going to your ped with any and all of these types of questions and issues; that&#;s what they&#;re there for!

I&#;ve read not to transition from bottles to sippy cups and just go straight to cups. Why is this?

Although the American Academy of Pediatrics has no official stance on sippy cups, there are many other experts&#;especially speech therapists and dentists&#;who do caution against too much reliance on sippy cups after you make the transition from bottles. That&#;s because of two main reasons:

• Oral motor delays and dental consequences. Extensive use of spouted cups may cause oral motor delays or cause your little one&#;s teeth to unnaturally shift. If your little one is exclusively drinking from a spouted cup, they may not learn to develop what experts call a &#;mature swallow pattern.&#;
• Tooth decay. Sippy cups are convenient and easy to drink from, and if your toddler becomes too used to one, it can cause tooth decay (especially if there&#;s milk inside) and can affect your child&#;s hunger level for real food.

Does this mean you should ditch the sippy cup completely? Definitely not; It&#;s totally up to you. Maybe you choose to use them just for on-the-go, or only at mealtime. But it is something to keep in mind as you make the bottle-to-cup transition.

A straw cup like the Zoli is a good alternative to a soft or hard spout cup. If you want to go right to an open cup, I love the ezpz Tiny Cup for beginning drinkers.

Read time: 5 minutes

What to know about choosing a baby bottle

• What to look for in baby bottles: shapes, sizes, and materials

• How to know what&#;s best for your baby when it comes to bottles and nipples

Whether you&#;re feeding your little one formula or expressed breast milk, navigating the wide selection of bottles and nipples can feel like a daunting task. As every baby is different, bottles and nipples are certainly not one-size-fits-all.1 It may take some experimenting to find what bottle works best for you and your baby.

What materials do baby bottles come in?

Bottles are made of a variety of materials: plastic, silicone, glass, and even stainless steel.

Plastic bottles are lightweight and inexpensive. Some bottles require a disposable plastic bag liner, which can be helpful for cleaning but requires purchasing bags on a regular basis.

Silicone bottles are softer and more flexible than plastic but may be a more expensive option.

Glass Bottles are sometimes chosen instead of plastic. Glass is long-lasting, is easy to clean, and does not contain the chemicals that plastic bottles may &#; should that be a concern.2,13 The downside is that they are heavier and prone to breakage. Silicone sleeves for glass bottles can be purchased which may help with grip and minimizing the possibility of breakage.

Stainless steel bottles have many of the advantages of glass without being as breakable. Yet it can be difficult to see how much milk is left in the bottle, and these are also a pricier option.

Read more: Everything You Need to Know about How to Prepare and Store Infant Formula

What types of baby bottles are available?

Angle-neck bottles are bent at the neck so that less air is likely to get into the nipple. Some parents think these are easier to hold as well. However, the design makes them a little harder to clean.

Disposable-liner bottles come with a plastic pouch that fits inside the bottle. As your baby drinks from the bottle, the plastic collapses without letting air in. This is claimed by the manufacturers to help prevent the formation of air bubbles in the bottle, which can increase gas in your little one&#;s tummy if swallowed. They are convenient (less cleaning!), but not as eco-friendly and the liners can get expensive if you&#;re exclusively bottle-feeding.

Vented bottles have a straw-like vent that goes through the center. The design claims to eliminate air bubbles that may increase gas in your baby. Despite a lack of evidence that these reduce gas and colic, many parents swear by them. Keep in mind that these extra parts do mean extra cleaning.

Wide-mouth bottles are shorter and wider than typical bottles. They also use wider nipples that claim to mimic a mother&#;s breast and nipple. If you are nursing and bottle-feeding, your baby may prefer the feel of this bottle best &#; but not always! These bottles tend to be easier to clean.

Read about: How to Supplement my Breastfed Baby with Formula

If you are wondering which bottle may work best for you and your little one, our team of registered dietitian nutritionists, fellow moms, and lactation specialists, are available from Monday &#; Friday 8 am &#; 6 pm (ET) to help figure out what may be going on. Chat now!

Bottle Sizes

Bottles typically come in 4-ounce and 8-ounce sizes. Start small when your baby is a newborn and use larger bottles once your baby starts to consume more milk at each feeding.

Read more: Should I Feed On Demand or on a Schedule?

What type of nipple should I choose for the bottle?

Nipple Material

Most nipples are made of clear silicone. However, some nipples are made with latex, which could cause an allergic reaction in sensitive infants.4 Chat with your doctor before using a latex nipple or pacifier to discuss their recommendations.

Note that the flexibility of the nipples can range very much between brands!5,

Nipple Shapes

Almost every bottle nipple claims to imitate a mother&#;s nipple and are available in different shapes. Standard nipples are long with a narrow base and are typically easy for baby to use. Other nipples have a wider base with varying nipple lengths.

Some experts recommend that breastfeeding babies most easily latch deeply on a nipple that have a wider base with a gentle slope down, versus an abrupt widening to the base.5,6, Nipple length can be a factor as well. If the nipple is too long for your baby, they may gag. If it&#;s too short, they may have trouble keeping it in their mouth.6,

Bottom line: Every baby is different! It may take some trial and error to discover which nipple shape and length may work best for your little one.

Read more: How Do I Relieve Gas in my Formula or Bottle-Fed Baby?

Nipple Flow Rates

Bottle nipples come with different-sized openings for milk to flow through. They are often labelled with levels (0 or 1 being the slowest) or &#;slow flow&#;. In reality though, the flow can be very different among brands, levels, and even within the brand or package.6,7,8

If baby is having trouble with the flow, make sure that baby is upright and the bottle horizontal (but tilted enough to keep air out of the nipple). Watch for signs of frustration or taking a longer than usual time to feed, which may mean baby is ready for the next size.

The rule of thumb is that younger babies typically take 2-3 oz in 10-20 minutes and older babies take 3-5 oz in 10-15 minutes.6,

Read more about correct positioning while bottle feeding: What Is Paced Bottle Feeding?

For more information, please visit silicone feeding bottles.