by Tanya Lieberman, IBCLC, with Amy Peterson, IBCLC

We’re very pleased to share an interview about bottles and breastfed babies today. We asked Amy Peterson, IBCLC, co-author of Balancing Breast and Bottle: Reaching your Breastfeeding Goals, to answer our questions.

For those of you who combine bottles with breastfeeding – whether you’re pumping at work, supplementing, or use a bottle for occasional separations – bottle and nipple selection can be confusing. For those of you whose babies refuse bottles, it can be very frustrating!

We hope that the information she shares below is helpful. Amy offers more information on bottlefeeding breastfed babies on her website.

Many bottles are advertised as “easing the transition from breast to bottle” and back again. What do you think of these claims? Are they independently verified?

These claims are very misleading. Just as every mother’s breast has a unique shape and flow, every baby has a unique suck/swallow cycle. What works well for one baby might be terrible for another. Parents need to observe their own baby sucking on a bottle nipple and analyze if the latch and swallow look similar to that on the breast. In our book, we use a tool called the SIMPLE Method that guides parents step-by-step on how to choose a bottle nipple for their own baby’s unique latch.

We are not aware if such advertising claims have been verified. However, we do know that this type of marketing is in violation of the International Code of Breastmilk Substitutes. This international health policy document, adopted by many countries excluding the U.S., is designed to protect families from underhanded marketing ploys such as words or pictures idealizing artificial feeding. Comparing a bottle to breastfeeding—even if it contains breastmilk—is idealizing that brand.

In our professional experience of helping babies combine breast and bottle-feeding, we have found that the nipples which claim to be best for breastfed babies are often the worst choice. The bottle nipples that are best for breastfed babies have a gradual transition from tip to base.

You and your co-author tested 37 bottles. What were the features you were comparing, and what did you learn about the range of bottles that you’d most want parents of breastfed babies to know?

We tested two different aspects of bottle nipples. First, we measured dripping by looking at the number of drips and the size of each drip. Then we hooked up bottles to a hospital grade breast pump to determine how fast bottles flow. After performing these tests, we compared the results to see if bottle dripping and flow rate were related.

The results were surprising. First of all, about half of the nipples, regardless of a non-“no drip” label stopped dripping within five seconds of tipping them upside-down. That was important for us because many bottle companies claim their nipples are “no drip,” implying that bottles that don’t drip are a better choice. To rule out the importance of dripping, we did further testing.

Second, we measured the size of the drip for those bottles that did drip. The most important thing we found was dripping does not equal a higher amount of liquid. Bottles that appeared to drip a lot often had less volume. Frequently it is assumed that a fast dripping bottle has a large amount in the drip. We discovered that a bottle may drip frequently, but with a low output. So, it is impossible to judge the size of the drip with the naked eye. Stated another way, the number of drips doesn’t mean more liquid is coming out.

As for flow, the term “slow” is not standard. To determine flow, we hooked up bottles to a hospital grade breast pump and measured the amount of liquid collected after 20 cycles. We found there was a wide range of “slow.” For example, the fastest nipple was eleven times faster than the slowest nipple. Following testing, we ranked nipples from slowest to fastest in Appendix C of Balancing Breast and Bottle. This is important because if a nipple flows too quickly, a baby’s suck will become disorganized. Likewise, a nipple might be too slow for some babies. A parent needs to watch their baby’s response to bottle-feeding rather than relying on package labeling. If a parent thinks the bottle is flowing too fast, try a different nipple in the package, and/or try a different brand.

The most fascinating results came from comparing the data of these two tests (drip and flow). Dripping is different than flow; they are not related. Most breastfeeding books suggest turning a bottle over to see how fast it drips in an effort to select a bottle with a slow flow. This suggestion is not accurate. We tested a nipple that dripped an average of 56 times when tipped over, but had a slow flow. Then, we looked at a no-drip nipple and much to our surprise, found it flowed 10.6 times faster. Big difference! Dripping is not related to flow.

Parents are often advised to begin breastfed babies on “slow flow nipples,” but even nipples advertised as “slow flow” can seem very fast. Are there any that are as slow as you think is appropriate?

As mentioned earlier, the term “slow” is not standardized. Nonetheless, it is important to begin with a slow nipple. If a nipple flows too quickly, a baby’s suck will become disorganized. For breastfeeding babies, it is best to choose a flow that mimics mom’s flow. For this reason, it is hard to say one or two brands are “best” since flow varies from mother to mother. Likewise, a nipple might be too slow for some babies. This is why we ranked the bottles and listed them in our book.

It is also important to remember that flow is only one aspect of choosing a bottle. If the baby’s mouth placement is wrong, regardless of the flow, baby will bring bad habits to the breast and still be in danger of early weaning.

For parents who are struggling to get their breastfed babies to take bottles, and who are exploring different bottles, what should they be looking for?

Moms need to consider the nipple shape and their baby’s mouth placement on the nipple. Ideally, the nipple chosen will gradually flare from the nipple length to the nipple base. This shape allows the tip of the nipple to reach far back into the baby’s mouth as the breast does, and then helps the baby to feed with the mouth open. Quite often a “narrow neck” nipple has a shape that reaches far into the baby’s mouth and allows for gradual widening of the baby’s lips.

A shape that often does not work well is a wide neck nipple where the nipple length meets the nipple base at a right angle. This nipple shape promotes what we call “straw” sucking, where the baby’s mouth closes around the length of the nipple and doesn’t open for the base. When babies “straw” suck on a bottle nipple, we often see gaps in the corners of the baby’s mouth which leads to leaking milk, gulping air, etc. This is quite different than breastfeeding.

One bottle feeding method is called “paced feeding.” Can you describe it and explain why it might be helpful to a breastfed baby? What are some signs that a baby is becoming overwhelmed while bottle feeding?

Paced feeding refers to helping a baby eat more slowly from the bottle. Pacing became popular in 2002, before flow had been studied. The idea behind pacing is that by helping the baby rest briefly during bottle-feeding, moms can more closely mimic how the baby naturally feeds at the breast. When a baby breastfeeds, the mother has several let-downs during the feeding. Between let-downs, the baby’s sucking slows and baby can rest briefly. If a baby is feeding from a fast flow “slow flow” nipple, the suck/swallow will be disorganized. Pacing helps the baby have rest periods while bottle feeding that naturally occur at the breast. Now that we know flow can be controlled by choosing an appropriate nipple, we have another technique in our bag of tricks to help babies be more coordinated when feeding from a bottle.

It is important to note that most babies can pace themselves once they master bottle-feeding with the right nipple. How do you pace? First, listen for swallowing while the baby is breastfeeding, noting when the baby naturally pauses and rests. Then apply the same rhythm to bottle-feeding. Also of importance is positioning. With bottle-feeding, support the baby in a more upright position because the flow of some bottles increases when the baby is laying back to feed (another element we tested).

Do all breastfed babies require pacing? No, in fact, imposing pacing can disrupt the natural feeding rhythm of a baby and cause harm when over used. Babies who are “good” feeders, meaning they have a normal, rhythmic suck/burst cycle, do not need pacing. It has been our experience that once a baby has mastered bottle feeding, it is no longer necessary for the parent to impose pacing.

Some signs of a poor bottle-feed include gulping, catch-up breaths, fast feeds, leaking milk from the sides of the mouth or down the chin, baby who has a furrowed brow looking very concerned, and a baby who pulls away from the bottle. For these babies, nipple shape and flow need to be double checked, and this becomes a good time to use pacing. Pacing also is an excellent technique for NICU and other high risk babies that are having feeding difficulties.

Lastly, we would like every caregiver who uses a bottle to know that dripping bottles given before a baby begins sucking usually cause the baby to pull back or flat out refuse the bottle. Caregivers need to be sure the nipple is not dripping when the bottle is offered to the baby. Allow the bottle to stop dripping or keep the milk tipped down in the bottom of the bottle. This topic is further explored on our website.

 Tanya Lieberman is a lactation consultant (IBCLC) who has helped nursing moms  in hospital and pediatric settings.  She writes and produces podcasts for several  breastfeeding websites, including  Motherwear,  Motherlove Herbal Company, and  the Best for Babes Foundation.  Tanya recently authored Spanish for Breastfeeding Support, a guide to help lactation consultants support Spanish-  speaking moms.  Prior to becoming a lactation consultant she was senior  education policy staff to the California legislature and Governor, and served as a  UN civilian peacekeeper.  Tanya is passionate about supporting nursing moms, and especially to eliminating the barriers so many moms face in meeting their breastfeeding goals. She lives in Massachusetts with her husband, her 8 year old son and her 1 year old daughter.