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Are breasts ever completely empty?

Breastfeeding mothers often wonder if it’s possible to completely empty their breasts. The short answer is no – breasts are never 100% empty. However, some key factors determine how thoroughly breasts can be drained during feeding or pumping. In this article, we’ll explore the anatomy of the breast, how milk production works, and strategies to optimize milk removal.

Anatomy of the Breast

To understand milk removal, we first need to understand the basic anatomy of the breast. The breast contains 15-20 milk-producing lobes organized like spokes on a wheel. Each lobe is composed of many smaller lobules where milk is produced. The lobules drain through a series of ducts that converge into the nipple.

Behind the lobes sits a layer of fatty tissue that gives the breast its size and shape. This tissue swells during pregnancy and breastfeeding in response to hormones like progesterone, prolactin, and oxytocin. These physiological changes prepare the breast to produce and deliver milk to the infant.

How Milk Production Works

Milk production is an ongoing process controlled by hormones and influenced by frequent milk removal. Here’s how it works:

– Hormones signal the mammary glands to extract nutrients from the bloodstream to synthesize breastmilk.

– As milk accumulates in the alveoli (small sacs within the lobules), it puts pressure on the ducts, signaling more milk production.

– Removing milk allows more milk to accumulate, maintaining the supply. Milk removal occurs during breastfeeding or pumping.

– The more often milk is removed, the more milk is produced. Supply matches baby’s changing needs.

– Some milk always remains in the breast – this is normal. The remainder helps signal the body to keep producing more milk.

Factors Limiting Milk Removal

If milk production depends on frequent drainage, what limits how thoroughly breasts can be emptied?

Milk Production Rate

The rate of milk synthesis limits how much milk can accumulate between feedings. During the first months of breastfeeding, milk production is highest – around 25-35 oz (750-1050 ml) per day. As solids are introduced, the production rate gradually decreases but continues as long as breastfeeding occurs.

Breast Storage Capacity

Storage capacity refers to the maximum amount of milk that can pool in the breast between feedings. Storage capacity varies among women, ranging from a few ounces to over 20 oz (600 ml). Breasts with larger storage capacity can accumulate more milk before becoming full.


As the breast fills, increased pressure on the ducts slows milk production. This biological feedback inhibition prevents engorgement. A comfortable level of fullness indicates an optimal production rate and storage capacity.

Milk Removal Reflexes

The milk ejection reflex causes milk to flow down the ducts toward the nipple. This reflex is triggered by baby suckling or the pump. Ejection continues for a few minutes and then milk leakage slows. Some milk remains in the ducts that cannot be expressed by suckling or pumping alone.

Maximizing Milk Removal

While the breast cannot be fully emptied, several techniques can optimize drainage:

Effective Breastfeeding

Correct latch and feeding on cue allows the infant to remove the most milk. Paying attention to swallowing indicates when the ejection reflex finishes. Switching sides when swallowing slows helps drain both breasts thoroughly.

Efficient Pumping

Using a hospital-grade pump with appropriate flange size promotes efficient pumping. Single pumping each breast completely is more effective than double pumping partially. Pumping after feedings can remove residual milk.

Drainage With Gravity

Some women use gravity to drain any leftover milk by leaning forward. Others may hand express after nursing or pumping to massage milk down the ducts.

Time Between Feedings

Aim for at least 2-3 hours between nursing or pumping sessions. Allowing time for milk accumulation promotes fuller drainage at the next feeding.

Hydration and Rest

Good hydration and adequate rest support milk production. Stress inhibits the milk ejection reflex, so relaxation techniques can improve drainage.

How Empty is Empty Enough?

There is no precise way to measure how much milk remains in the breast after feeding or pumping. However, signs of thorough removal include:

– Light, soft breasts after nursing or pumping

– Infant seems satisfied after nursing

– Little or no leakage between feedings

– Pumping yields little after 15 minutes

As long as the infant receives sufficient milk, and weight gain is on track, drainage is likely sufficient. Any remaining milk helps maintain ongoing milk synthesis.

When to Worry About Incomplete Emptying

In some cases, incomplete drainage can cause issues:

– Discomfort, leaking, plugged ducts, or mastitis due to milk buildup

– Poor weight gain in the infant suggesting insufficient milk transfer

– Decreasing milk supply from lack of milk removal

If any of these occur, speak with a lactation consultant. They can assess breastfeeding, pumping, and the baby’s intake to determine if there is a problem with drainage and how to address it.


While no mother can completely empty her breasts, understanding milk production and removal can help optimize drainage. Allowing sufficient time between nursing or pumping, using effective techniques, and recognizing signs of thorough removal all help clear the breasts as thoroughly as possible. This maintains comfort and milk supply while ensuring baby gets the milk they need to thrive.

Frequently Asked Questions

Why do some women leak milk all day if breasts aren’t full?

Some women may continually leak small amounts of milk even when the breasts feel soft. This results from an overabundant milk supply and high baseline prolactin levels. The best solution is to pump to comfort to avoid engorgement and gradually decrease production to match baby’s needs.

Do fuller breasts make more milk than emptier breasts?

Actually, milk production relates to how much milk is removed over time, not how full the breasts become. Overly full breasts can lead to blocked ducts and mastitis which inhibits milk synthesis. The emptier the breasts at the end of a feeding, the more milk they can accumulate for the next feeding.

Will my milk supply decrease if I can’t fully empty my breasts?

As long as your breasts feel softer after feeding/pumping, and your infant is gaining weight normally, your supply should stay ample. The key is ensuring complete removal at each session, not necessarily achieving 100% emptying which isn’t possible. Talk to a lactation consultant if you have any concerns.

Should I pump after nursing to get more milk out?

Pumping after nursing can help drain any milk leftover in the breasts. This may provide comfort if the breasts don’t feel well-emptied. But routine pumping after nursing signals the body to overproduce milk. Only pump after feedings if necessary for comfort or if your baby is not gaining weight well.

Is it normal for pump output to decrease over a pumping session?

Yes, it’s very normal for pumped milk volume to decline after the first few minutes once the ejection reflex finishes. Remaining pumping helps drain any residual milk in the breast but won’t continue ejecting large volumes. Pay attention to when pumping output slows and switch breasts as needed.