Unintended consequences of the extended use of preemie flow rate bottle nipples to support breastfeeding There is a popular belief among many healthcare professionals and social media support groups that breast fed full term infants who require bottle supplements should use a preemie flow rate nipple. It sounds logical, with a very slow flow nipple the infant must suck harder to pull the milk from the bottle, thereby, strengthening their suck and ensuring bottle feeding is not “easier” than breast. This may be helpful in the first four weeks as breast feeding is being established; however, extended use of preemie flow nipples can result in unintended consequences by teaching compensatory suck patterns.

These compensatory suck patterns may have the opposite of the desired effect to complement breast feeding. Specifically, preemie flow rate nipples have been observed to reinforce multiple sucks per swallow, which can teach inefficient oral postures, and interfere with self-regulated suck(le)/swallow/breathe sequence. These increase energy expenditure that cause increased fatigue, and in some complex cases, resulting in failure to gain adequate weight or weight loss.

A good deal of attention is given to intake volumes with bottle supplement; however, energy expenditure during bottle feeding is equally important. As infants mature, and their suck strengthens, the preemie flow nipples provide an inadequate volume of liquid to trigger the swallow. In theory, the thought is that this reinforces continued suck(le) to stimulate milk flow; however, once the milk is expressed the infant then converts to 1-2 sucks per swallow at breast. The use of the preemie nipple does not make this conversion; thereby, sustaining multiple sucks (typically 3-4) per swallow.

Compensatory suck patterns also negatively impact facial/oral movements as can be seen in the photo. When an infant works to suck harder on the preemie flow nipple they learn to tighten the muscles along the lateral edges of the upper lip and along the corners of their mouths, often resulting in dimpling.

Muscle tension in these areas does not support a wide gape for optimal latch at breast. The infant may inadvertently learn facial postures and use of muscle tension that inhibit an optimal 120-140-degree latch angle at the corner of the mouth. Increased muscle tension has been clinically observed to interfere with the peristaltic anterior to inhibit posterior movement of the tongue as the infant over-engage the muscles of the tongue. To further compensate, the infant may drop the jaw and pulls cheek muscles inward in an effort to increase the oral space for more suction, which could result in over use of jaw compression, and sometimes, but not always resulting in the “snapback” sound as described above.

So, how can you tell if a preemie flow rate is helpful or is placing the infant at risk of developing maladaptive suck patterns or high energy expenditure?

1. How much time is required for the infant to complete a bottle? The time it takes an infant to complete a full bottle feeding provides helpful information about their efficiency and energy expenditure. These times can be prorated when considering partial bottle supplement volumes. If an older infant exceeds these timeframes they would benefit from increasing the bottle/nipple flow rate.

Newborn: 25-30 minutes – A typically developing full term newborn infant should be able to complete a full nipple in cradle hold head and shoulders supported upright with hips slightly forward.

Three-month-old: 20 minutes

Four-month-old: 10-15 minutes – Infants at this age are physiologically ready to transition to a supported upright seated position in the feeder’s lap with shoulders over hips.

Five months +: plus, or minus, 10 minutes or so.

Note: If the infant completes bottes far more rapidly the bottle/nipple flow rate may be too fast (even if the nipple says “slow flow”).

2. Do you hear popping sounds as the infant sucks, see cheeks pulling deeply inward or over use of the jaw as they suck on the preemie nipple? Although often assumed a characteristic of tongue tie, a popping, clicking or snapback sound is often heard with bottle feeding when the flow rate is too slow when the infant increases inner oral pressure by dropping the jaw too far down (over use of compression) which, breaks the seal between the posterior tongue and hard palate.

3. Does the infant have a high suck to swallow ratio? Infants should demonstrate 1 or 2 sucks for every swallow (1-2:1 SSR). If they have to suck 3+ (>2:1 SSR) times for every swallow they are simply working too hard. Rhythmicity and coordination of the suck/swallow with increased effort are also altered and create a mismatch between breast and bottle.

4. Does the infant show excessive sign of fatigue or does not complete bottles/meet daily intake volumes required for their age? Increased sucks per swallow also increase the amount of energy the infant expends, by sucking 3-4 times per swallow, they are working 3-4x harder throughout the entire feeding.

5. Do you see facial tension including dimples that look like “V” or “Y” at the corner of their mouth and/or tension through the nasolabial folds? If so, these are maladaptive suck compensations. If the answer is yes, this infant would likely benefit from a term, not preemie, nipple.

In the past several years there has been increased research and improvement in bottle/nipple technology that now allow more sophisticated selection of bottles to avoid teaching maladaptive suck compensations and better compliment breast feeding. For example, historically, we used to need to feed infants in a nearly bolt upright seated position in order to keep the liquid in the bottle level and the nipple half- filled. This is due to the pressure gradient in the bottle and far fewer nipple flow rate choices. These feeding techniques are no longer required for some bottles now on the market. For example, Dr. Brown’s bottles have zero pressure gradients and do not require that the liquid rest in a half-filled bottle to control the flow. The Playtex Drop-In Nurser allows you to adjust flow rate by either keeping or removing air from the bag. When we correct nipple flow rate (and in some case nipple shape) we typically observe decreased facial tension and more efficient, normal suck patterns within 3 days. In hospitals that discharge full term infants with preemie flow rate nipples care should be taken by pediatricians, outpatient lactation specialists and feeding therapists to monitor for maladaptive suck and feeding difficulties that might develop after discharge. The infant can then be introduced to a nipple flow rate appropriate for their age and feeding skills. References: Pados, B. F., Park, J., Thoyre, S. M., Estrem, H., & Nix, W. B. (2016). Milk flow rates from bottle nipples used after hospital discharge. MCN. The American Journal of Maternal Child Nursing, 41(4), 237–243. Pados, B. F., Park, J., Thoyre, S. M., Estrem, H., & Nix, W. B. (2015). Milk Flow Rates From Bottle Nipples Used for Feeding Infants Who Are Hospitalized. American Journal of Speech-Language Pathology, 24(4), 671–679. Jackman, K.J. (2013) Go with the Flow: Choosing a Feeding System for Infants in the Neonatal Intensive Care Unit and Beyond Based on Flow Performance, Newborn and Infant Nursing Reviews, Volume 13, Issue 1, 2013, Pages 31-34. https://www.drbrownsbaby.com/medical/wp-content/uploads/2016/08/DBM-Milk…

About Allyson Goodwyn-Craine

Allyson Goodwyn-Craine M.S., CCC-SLP, BCS-S, CLC is a Pediatric Speech-Language Pathologist/Feeding Specialist who is a Board Certified Specialist in Swallowing and Swallowing Disorders and Certified Lactation Counselor. Click here to contact Allyson