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Does your breast become big due to pumping?

Many women wonder if pumping their breasts will lead to increased breast size over time. There are a few factors that determine breast size, and pumping can play a role for some women. Here’s an overview of how pumping may or may not impact breast size.

What determines breast size?

Breast size is determined by several factors:

  • Genetics – Breast size is largely determined by genetics and DNA. If your mother or other close female relatives have large breasts, you are more likely to as well.
  • Body weight – Breast tissue is made up of fat, so a higher body weight is usually correlated with larger breast size.
  • Breast tissue density – The amount of fibrous and glandular tissue in the breasts also impacts size. Dense breasts may be smaller.
  • Hormone levels – Estrogen levels play a role in breast growth and development.
  • Pregnancy/breastfeeding – Pregnancy and breastfeeding cause changes in hormone levels and breast tissue that for many women increase breast size.

Does pumping increase breast size?

Pumping breast milk does not permanently increase breast size for most women. However, some temporary or minimal changes may occur:

  • Engorgement – Pumping when breasts are full and engorged can temporarily lead to increased size and firmness.
  • Milk production – The glands and milk ducts may become larger and more developed to accommodate increased milk production.
  • Blood flow – Pumping increases blood flow to the breasts, which can cause slight temporary swelling.

These effects are not permanent, and breasts will likely return to their pre-pumping size once regular pumping stops. For women who were previously small-breasted, pumping may bring them up one cup size at most.

When can pumping increase breast size?

For some women, consistent, long-term pumping can contribute to increased breast size compared to pre-pregnancy or pre-nursing. This is most likely if:

  • Pumping sessions are long and frequent, like every 2-3 hours.
  • Pumping continues consistently for several months or years.
  • The woman was originally small-breasted, such as A or B cup.
  • The woman gains weight while pumping, adding fat tissue to the breasts.

During lactation, prolactin and oxytocin hormone levels remain elevated, which enhances breast tissue development. For those pumping frequently for sustained periods, this effect may be amplified over time.

How pumping can increase breast size:

Here’s a closer look at the possible ways frequent, long-term pumping may contribute to an increase in breast size:

  • Milk gland growth – The glands and milk ducts become larger and more developed, expanding the breast tissue.
  • Fat tissue increase – Pumping signals the body to send extra nutrients to the breasts, which are stored as fat tissue.
  • Fluid retention – Pumping brings increased blood flow and fluids to the breast area, slightly enlarging breast tissues.
  • Hormone stimulation – Prolactin and oxytocin, which stimulate breast growth and milk production, remain high with frequent pumping.

For most women who see size increases, it is typically not a dramatic change. However, some women may go up 1-2 cup sizes with very frequent, long-term pumping.

Factors that impact breast size changes

Several factors influence whether and how much pumping could increase breast size for an individual:

Factor Impact on Breast Size
Genetic predisposition Women with genes for larger breasts see greater increases.
Weight gain Weight gain during pumping adds fat tissue to breasts.
Pumping frequency/duration More frequent, longer pumping further stimulates milk glands.
Original breast size Women with smaller breasts pre-pumping are more likely to go up a size.
Age Younger women’s breast tissue is still developing and may be more sensitive to stimulation from pumping.

As this table demonstrates, a woman’s unique physiology and how she pumps play a significant role in any potential breast size changes.

Steps to maximize breast size increase with pumping

If your goal is to increase breast size with pumping, here are some tips that may help:

  1. Start pumping soon after giving birth when hormone levels are highest.
  2. Pump frequently, at least every 2-3 hours if possible.
  3. Pump for 10-15 minutes per session to fully empty the breasts.
  4. Pump during the night, even if you need to set an alarm to wake up.
  5. Massage and compress the breasts while pumping to increase milk drainage.
  6. Maintain a calorie-rich diet with nutrients like fenugreek to support milk supply.
  7. Stay well hydrated by drinking plenty of fluids each day.

Following lactation guidelines and pumping around the clock for many months can stimulate breast tissue growth. However, results will vary greatly by individual.

Risks and considerations with breast pumping

While some women may wish to pump frequently in hopes of increasing bust size, there are some risks and considerations:

  • Overpumping can lead to painful mastitis or damage milk glands.
  • Excessive pumping without sufficient breast draining can cause engorgement.
  • Pumping too much can decrease your milk supply over time.
  • Frequent pumping is very time consuming and tiring.
  • Any size increases will likely diminish once pumping stops.
  • Significant size increases are not guaranteed even with frequent pumping.

Speak with a lactation consultant to come up with a healthy, reasonable pumping schedule based on your body’s needs.

Alternatives to increase breast size

If pumping does not give you your desired results, here are some other options for increasing breast size:

  • Breast augmentation – Implants provide immediate, controlled, dramatic bust enhancement.
  • Natural breast enhancement – Supplements may gradually increase breast tissues naturally over time.
  • Breast fat transfer – Liposuctioned fat from other areas can be injected into the breasts.
  • Birth control pills – The estrogen may stimulate breast growth for some women.
  • Therapeutic massage – Repeated massage may increase blood flow and gradually build breast tissues.

Discuss options like these with your doctor to decide if they may be appropriate for your goals. All carry their own risks and benefits.


For most women, pumping does not dramatically alter breast size after pregnancy and breastfeeding. However, some minimal to moderate enlargement is possible, especially with very frequent, long-duration pumping over many months. Factors like genetics, weight changes, original breast size, and hormone levels impact results. While sustained pumping may bring gradual changes for some women, it comes with health risks and is extremely time consuming. For significant breast enhancement, alternatives like implants or fat transfer may be more suitable and realistic options.