Breastfeeding With a Supplemental Nursing System

There could be several reasons why a baby may need supplemental breast milk, donor milk or formula in addition to direct breastfeeding. Perhaps a mother has a very low milk supply and her baby isn’t gaining weight. Or a baby may not be getting enough milk because he has a poor latch or tongue function.

Traditionally this supplemental milk has been fed by spoon, syringe, cup-feeding or bottle. But there is another option; supplementing at the breast using a supplemental nursing system. This article looks at how supplemental nursing systems work, when to use one, their pros and cons and tips for smooth feeding.

How a supplemental nursing system works

A supplemental nursing system incorporates a container of milk connected to a length of flexible feeding tube. The free end of the tube is held or taped to run alongside mother’s nipple so that her baby takes the tube and nipple together in his mouth when he latches. Alternatively the tube can be inserted in the corner of his mouth part way through the feed after the breast has been emptied. While the baby breastfeeds, he also gets supplemental milk fed to him via the small tube. As long as baby breastfeeds with a good latch and suction, with his lips sealed around the breast, milk will flow up the tube with much the same principle as sucking up a straw.

Controlling the rate of flow of milk

It is important to get the flow of supplement at the right speed; too fast and your baby may get too much milk to cope with, too slow and an underweight baby may not have the stamina to keep feeding long enough. The rate of flow of milk up the tube varies with the diameter of the tube and where the container is in relation to the baby—the flow is slower if the bottle is positioned below the baby and faster if the container is positioned above baby’s head. There is more information about tube sizes, flow rates and cleaning instructions in Homemade Supplemental Nursing System. Stay in contact with your IBCLC lactation consultant or health professionals while using a supplemental nursing system.

When to use a supplemental nursing system

The at-breast supplementer has many potential uses

  • For topping up a baby if a mother has insufficient glandular tissue or another reason for low milk supply.
  • Keeping an adopted baby fed at the breast to give the experience of breastfeeding.
  • Keeping a baby interested in latching when encouraging a baby back to the breast after a period of bottle feeding or while a mother is relactating.
  • The tube can be used as part of a finger feeding exercise for suck training.

At-breast supplementing can be used indefinitely—for as many weeks, months or years as you both like, with as much milk as you’re able to produce and even if you produce none at all—without your baby losing interest in nursing at your breast. It is, after all, his food source!

A baby finger feeding with a supplemental nursing system
Finger feeding

Pros and cons of supplemental nursing systems


  • The breasts are stimulated to make more milk by additional suckling.
  • Baby gets more practice at breastfeeding properly, if he doesn’t feed correctly, milk won’t come up the tube.
  • Mother enjoys “breastfeeding”.
  • There is no chance baby will start to prefer a bottle instead or stop breastfeeding correctly (nipple confusion).
  • Eliminates a baby’s frustration with slow flow from the breast when milk supply is very low.
  • Baby associates feeling full with the breast and this reinforces his desire to breastfeed.


  • It can be very fiddly to use until you get the hang of it.
  • It is difficult to clean the little tubes thoroughly.
  • The system can leak, particularly home made versions.
  • Some babies can’t seem to suck milk up the tube or are not able to get very much. A very underweight baby may still fall asleep at the breast without having fed well.
  • It isn’t a suitable method if a baby isn’t latching or is latching so badly as to make his mother’s nipples painfully sore.
  • Some babies are aware of the tube and it can disturb their latch, tweaking it into different positions may help.
  • Some babies try to suck on the tube like a straw rather than breastfeed correctly.
  • The tube could reach too far into the baby’s mouth and cause gagging. Taping the tube to the breast with medical tape so that it aligns with the end of the nipple can avoid this.

What supplements can be used in a supplemental nursing system?

This will depend on your individual circumstances. Supplements could be a mother’s own expressed breast milk, donor milk or formula supplements if needed.

Types of supplemental nursing system

There are two main commercial supplemental nursing systems (SNS); the Medela SNS or the Lact-Aid. It is also possible to make a homemade version, see Homemade Supplemental Nursing System.

Diana West and Diane Wiessinger have written a very useful article discussing supplementing at the breast in LLLI’s Breastfeeding Today. The authors discuss the differences between the types of supplementer you can buy and offer practical tips and suggestions to use them successfully. See Long-Term At-Breast Supplementing for the Breastfed Baby, Breastfeeding Today, 2010.

Video of Breastfeeding Using a Lactation Aid with Dr. Jack Newman

This clip shows a homemade supplementer using a 5fr or 6fr feeding tube. A little surgical tape or a sticking plaster can be used to stick the tube in place along mother’s breast to prevent the possibility of the tube slipping from the baby’s mouth towards his throat which could cause gagging. See Homemade Supplemental Nursing System for further information on how to make your own.

Video using a commercial system by Natasha Batsford

Get help with breastfeeding

There are lots of ideas to increase your baby’s intake of breast milk even if you can’t produce a full supply. See How to Make More Breast Milk and contact your IBCLC lactation consultant for more support. Your lactation consultant can help you find the best latch and position for you and your baby, check your baby’s tongue function, and help with breastfeeding management.


A supplemental nursing system allows a baby to take top ups of supplemental milk directly at the breast while breastfeeding. Supplementing this way has various pros and cons but is another option to consider alongside bottles or cup feeding. A very underweight baby who has not been gaining weight can still tend to fall asleep at the breast without having swallowed plenty of milk, even with a supplemental tube in place. It is important to monitor weight gains and dirty nappies to establish whether your baby is getting enough milk. Stay in contact with your IBCLC lactation consultant or health professionals while using a supplemental nursing system.