Milk Let-Down - Milk Ejection Reflex (MER)

Increasing Your Breast Milk Supply by Encouraging MER (Milk Ejection Reflex) or “let down”

What is the MER (Milk Ejection Reflex) or "Let-Down"? In between feedings, the clusters of alveoli and the milk ducts fill up with milk. This makes the breasts feel heavy when it is time for the baby to nurse. As the baby sucks, stimulation of the nipple causes the mother’s pituitary gland, located in the brain, to release oxytocin. Oxytocin causes contractions in the muscle cells that surround the alveoli. These contractions squeeze milk out of the alveoli and cause the ducts to expand, pushing milk toward the nipple. In a beautiful system of give and take, the breast propels milk as the baby sucks.

Some mothers can feel this hormonally induced release. They describe it as a tingling or rushing sensation. Surprising at first, most women come to experience it as a pleasant, and soothing sensation. This is referred to as the “let-down,” or milk ejection reflex (MER). There are mothers who do not experience the sensation directly, but observe that the other breast will begin to leak or the baby will start to gulp. Other signs that a milk ejection reflex (MER) is occurring are a sense of thirst, or a sudden feeling of relaxation or even sleepiness.

The milk ejection reflex (MER) can be affected by stress, anxiety, or pain. This is why is it so important for breastfeeding mothers to have the support and care of their families as they recover from childbirth.

Giving your breast just the right touch can help trigger your MER, especially if your breasts are engorged, your nipples are sore, or your baby is impatient.

1. Apply a warm compress to your breast, such as a warm towel or cloth diaper soaked in warm water.
2. Then, with your fingertips, stroke from the top of the breast down and over the nipple, using a light feather touch. This helps you relax and helps stimulate your oxytocin.
3. Using a motion similar to the one you use when examining your breasts, massage the milk-producing glands and ducts by pressing the breast firmly with the flat of the fingers into the chest wall, beginning at the top and working in a spiral down toward the areola. Massage in a circular motion a few strokes at a time before moving to another spot.
4. While leaning forward, gently shake your breasts, allowing gravity to encourage the stimulation to release milk.
5. Gently roll the nipple between your finger and thumb.

You may feel the milk ejection reflex or notice your breasts leaking or you may not. You are likely to pump more milk faster if you pump both breasts at the same time. You do not need to feel or be aware of the milk ejection reflex in order to make milk. Some women may feel thirsty, sweaty, sleepy, or dizzy during a let down. However, many women do not feel this milk ejection response ever in their whole breastfeeding experience. Some women only become aware of it after the first few weeks. This has absolutely no bearing on milk supply. Breast compressions, while pumping, can be very effective at increasing the amount expressed, it may be a bit awkward at first, but it can be done (mothers have fixed the cups so that they sit inside the bra and then use compressions) or the partner can do it.