Your breast size and shape doesn't determine your milk production

Lactating human breasts are diverse on the outside, and diverse on the inside. The size of our breasts doesn't determine how much milk our breasts can make.

• The most important thing that sets your milk supply is how frequently milk is removed from your breasts in the first days of your baby's life, ongoing.

• Size and shape are determined by variations in amount of fat tissue within the breast rather than variations in amounts of glandular tissue. This is why a very delicate breast is as capable of satisfying a baby's milk needs as a very generous one.

Sometimes, a woman might have an anatomic or metabolic condition which interferes with her capacity to make milk - but even then, the best thing to do if you hope to breastfeed is to give it your all out hottest go, and see what happens.

My own story

Once, about thirty-five years ago, in the last weeks of my first pregnancy, I lay on an examination couch while a midwife checked my belly for the baby's size and lie. I mentioned I was worried I mightn't make enough milk because I had such delicate breasts. "Small breasts", I would have said back then.

"Have they been changing?" she asked. I explained that my breasts had been hot and tight and sensitive since early in my pregnancy, as a network of purple veins became visible under the skin.

"Well, those are normal breast changes during pregnancy," the midwife said. "But let me take a look." I lifted up my blouse and bra, lying there on the couch.

I don’t remember consenting before the midwife began to squeeze my breast and areola. It felt as though this happened quite suddenly, without warning. It felt completely wrong. It hurt. I can’t recall if any colostrum appeared but I quickly asked her to stop. I think the midwife was wanting to show me that I was already making milk.

Just before my baby arrived, however, I raised the same concern with another midwife, who began to talk kindly to me about her clients of Asian heritage, many with very slight bodies and petite breasts, "even smaller than yours", I remember her saying! - and how incredibly generous their milk supply could be.

It was that conversation, not the expression of colostrum, which helped me believe in my breasts. Perhaps my breasts had less fatty tissue than some other women's breasts, but they were dense with milk glands. My breast shape didn't put me (or you, too, if you have petite breasts) at risk of low milk supply.

Recommended resources

working breasts are diverse on the outside

Working breasts are diverse on the inside

You can find out about

• How to help your breasts make plenty of milk here

• Frequent and flexible breastfeeds here

• Insufficient glandular tissue here

• Inverted nipples and what to do in pregnancy here

• Nipple piercings, breast surgery, and milk supply here

• What causes low supply here.

Selected references

Gridneva Z, Rea A, Weight D, McEachran JL. Maternal factors, breast anatomy, and milk production during established lactation - an ultrasound investigation. Journal of Imaging. 2025;11(9):313 https://doi.org/310.3390/jimaging11090313.