Will the size of my breasts determine if I'm able to breastfeed?
Breasts come in all shapes and sizes, but breast size does not determine how much milk you will produce. You may notice a change in breast (and nipple) size throughout pregnancy and breastfeeding. Other breast changes (tenderness, blue veins showing near the surface of the breasts, nipples sticking out more, Montgomery Glands becoming more noticeable) are good signs you will be able to make all the milk baby needs. Feeding early after delivery (within the first hour) and often (about 8–12 times in 24 hours) will promote a plentiful milk supply.
Small Breasts
Women with small breasts can successfully and exclusively breastfeed their babies. Milk is made in the glandular tissue of your breast; breast size is dependent on fatty tissue. Get comfortable and position your baby so they are facing you to ensure they get a good, deep latch.
Large Breasts
Women with large breasts can successfully and exclusively breastfeed their babies, too. You may need to support your breast to take the weight off baby's chin and prevent it from covering baby's nose. Pillows for extra support and placing a rolled-up towel underneath the breast to prop it up can be helpful. Just make sure you are not changing the shape of your breast or nipple by squeezing too much, and keep your fingers farther back, away from the areola. Finding a comfortable position so that baby can get a good, deep latch is important. The laid-back breastfeeding position can be especially helpful for large breasted women.
Storage Capacity
This refers to the amount of breast milk that can be stored in the breasts at one time. Storage capacity does not depend on breast size. Women with small breasts can have a large storage capacity, while women with large breasts can have a small storage capacity. Storage capacity does not determine your ability to make milk, but rather how much milk can be stored in the breasts before they are too full. Women can have different storage capacities in each breast.
Magic Number (Feeding Frequency)
Your magic number refers to the number of times you need to empty your breasts (by latching or pumping) in a 24-hour period in order to maintain a good milk supply. While your magic number may be greater if you have a smaller storage capacity and less if you have a larger storage capacity, it is best to feed your baby on demand by watching their hunger cues.
Regardless of breast size and storage capacity, the key to successful breastfeeding is understanding your baby's needs and responding to them. Every mother and baby pair is unique, and you will learn to recognize what your baby is "telling" you. Trust that your body is able to make enough breast milk for your baby and that you are capable of reaching your breastfeeding goals!
SOURCE: https://wicbreastfeeding.fns.usda.gov/breast-and-nipple-size-and-shape