Clinical Reference Systems: Pediatric Advisor 10.0

Description of the Let-Down Reflex (Milk Ejection Reflex)

When you breast-feed, your baby's suckling stimulates nerves in your nipple. These nerves carry a message to your brain, and the hormone oxytocin is released from your pituitary gland. Oxytocin flows through your bloodstream to your breasts, where it causes tiny muscle cells around your milk glands to squeeze milk out of the glands and into the milk ducts. This is known as the let-down reflex or the milk ejection reflex.

Once your let-down is working well (usually by 2 weeks after delivery), you may feel a pins-and-needles or tingling sensation in your breasts when you nurse or pump. Milk will usually drip from one breast while you are feeding on the other side. Sometimes your let-down will occur just when you hear your baby cry or think about nursing your baby. A well-functioning let-down reflex helps ensure your breasts get emptied and your baby easily obtains milk.

Sometimes a woman's milk ejection reflex doesn't work as well as it should. This can cause breast-feeding difficulties. For example, you may have problems emptying milk from your breasts, or your baby may not get enough milk.

Causes of a Poor Let-Down Reflex

Several situations may prevent the milk ejection reflex from working well, such as:

• severely sore nipples that cause you to tense up before each nursing
• stress, anxiety, and tension; for example, trying to pump breast milk during a short break at work
• being separated from your baby; for example, having a premature infant who is unable to nurse, making it necessary for you to use a pump to express breast milk
• previous breast surgery that has damaged the normal nerve pathways to the nipple, such as breast reduction or augmentation surgery. If you have altered sensation in your nipple after surgery (that is, your nipple is either somewhat numb or super-sensitive), it is possible that nerve damage from the procedure could interfere with your milk ejection reflex.

Ways to Trigger the Let-Down Reflex and Improve Milk Flow

The following suggestions can help trigger the let-down reflex and improve milk flow:

• Try to nurse or pump in a place that is familiar, comfortable, and restful.
• Drink a beverage whenever you sit down to nurse or pump.
• Play soft music or do relaxation exercises before you nurse or pump.
• Gently massage your breasts before you nurse or pump.
• Have your partner give you a backrub before you nurse or pump.
• Put a warm washcloth or heating pad on your breasts, or take a warm shower before you nurse or pump.
• If you are pumping because you are separated from your infant, put a photograph of your baby by the pump.