Small breasts can breastfeed just as well as big ones

It is the amount of fatty tissue that makes some breasts bigger than others.  In other words, the milk producing apparatus is about the same in both small and big breasts.  Therefore breast size is not linked to the ability to produce breast milk and breastfeed per se.  Even flat-chested women, who don't have practically any fat cells in their breasts, can breastfeed.  Besides, you really don't know your final breast size until after your first pregnancy, because the milk-producing cells and milk ducts grow and branch out a lot during the third trimester.

However, breast size does affect the breastfeeding relationship in at least two different ways.  First of all, many times the babies of large breasted women have some difficulty in latching on in the beginning because they have such a tiny mouth in comparison to the areola they are supposed to take into their mouth and suck on.  This problem usually goes away as the baby grows older.  A lactation consultant can help with the initial problems; for example, the mother can pump the milk during the early weeks while the baby is learning a proper latch, and the pumped milk can be fed to the baby in a bottle.

Secondarily, the research of Peter Hartmann has shown that the milk storage capacity varies a lot between women.  Breast milk is produced continually and it accumulates in the milk ducts between feedings.  During feeding, a baby typically empties about 70-80% of the milk in the breast.  Hartmann found in his studies that some women had 3 times as big a storage capacity than others - but that all of them produced the same amount of milk over a 24-hour period.  In general, bigger breasts of course would have a bigger storage but it was noted that breast size was not always a good predictor of production or storage capacity.

In practical terms it means that women with small storage capacity breasts need to nurse more often, and the babies take in less per feeding.  Women whose breasts have a larger storage capacity can 'deliver' more milk in one feeding, and so the baby needs to nurse fewer times per day.  This further confirms the need of cue feeding or demand feeding where the baby sets the frequency of breastfeeding - and not the clock or the pediatrician or the grandmother.

Tubular hypoplastic breast

There is one exception to the rule about breast size/shape and breastfeeding ability, and that is that some (very few) women have insufficient glandular tissue in their breasts.  In other words they simply don't have enough milk producing cells, and these women can then experience milk supply problems. This condition is called breast hypoplasia or hypoplastic breasts.

This kind of breast is underdeveloped (hypoplastic) in terms of the milk glands.  They lack normal fullness and may look like 'empty sacks', and may seem bulbous or swollen at the tip.  Many times hypoplastic breasts are widely spaced from each other, and narrow at the chest wall.  Due to lack of glandular tissue, they have an elongated or tubular form, and often are quite small.  The areola can be enlarged.  There may be a significant asymmetry.  The breasts don't grow during pregnancy and there is no engorgement when the milk is supposed to come in after giving birth.

Scientists don't yet know for sure the reason for this underdevelopment. One theory is that at least in some women it would be linked to too little progesterone, since progesterone mediates the growth of alveoli (milk making glands).

If you happen to have these tubular hypoplastic (under-developed) breasts, talk to a lactation consultant before giving birth.  There are measures you can take to try increase your milk supply and your chances of breastfeeding, such as

• have an unmediated birth if possible, and put the baby to the breast right after birth
• nurse often and on cue
• start to pump about three days after birth
• try the herbs fenugreek and blessed thistle or the drug domperidone
• breast compression technique to stimulate more letdowns

Discuss these and other options with the lactation consultant.  You may need to supplement with formula, so it is important to observe the baby's output of wet and dirty diapers and weight gain to make sure the baby is getting enough nutrition.  Remember also to be happy for whatever breast milk you produce and not blame yourself - even a little is better than none!  And if you don't get any milk at all (which does happen), remember it's not your fault.  For this kind of situation we can be thankful that the baby formula exists.

Plastic surgeons try to take the most out of women with hypoplastic breasts.  Since it is a true medical condition, they try to push these women to get implants to correct the deformity.  Having hypoplastic breasts is not any dangerous condition.  They look different, and as explained above, women with hypoplastic/tubular breasts often have difficulties in producing enough milk.  It is understandable to feel bad when you have deformed breasts, and there's nothing wrong if you wish to have it corrected.  Unfortunately the implants will only lessen the milk supply and the probability of successful breastfeeding, besides forcing the woman to go through several surgeries throughout her lifetime, and putting her to a high risk of serious complications and diseases. However, the choice is still yours, of course.

See also:

Breastfeeding and underdeveloped (Hypoplastic) breasts

Insufficient glandular tissue at Mothering.com Discussion Forums

Lactation failure due to insufficient glandular development of the breast Pediatrics. 1985 Nov;76(5):823-8.

Patient with insufficient glandular tissue experiences milk supply increase attributed to progesterone treatment for luteal phase defect. J Hum Lact. 1999 Dec;15(4):339-43.
In this one case, the woman was able to produce enough milk for her second child when she was treated with natural progesterone during that particular pregnancy. Progesterone stimulates the growth of the glandular tissue in breast (alveoli) during pregnancy.

Where’s the milk? Insufficient glandular tissue.
Insufficient glandular tissue (IGT) is a condition first described by Neifert in 1985. The initial series described 17 women who, despite frequent, unlimited feedings with good latch, were unable to establish more than a cursory milk supply. Other cases have been reported since the initial series. These women tended to have little or no breast changes during pregnancy, and more than the usual amount of asymmetry between the breasts. Some women with this problem have been reported as having disproportionately large nipple/areolar areas, “tubular shaped” breasts, and breasts which are widely spaced.

A link between polycystic ovarian syndrome (PCOS) and insufficient milk supply.

PCOS and Breastfeeding - an interview with Lesa Childers, talking about PCOS, low milk supply, and hypoplastic breasts.