Breast shape and size are determined genetically, but they can change as a result of pregnancy and lactation, intensive workouts, and sudden weight fluctuations. There may also be noticeable changes at certain points during the menstrual cycle.

The breasts can become bigger temporarily during pregnancy or when breastfeeding. Sometimes, breast shape can be related to weight gain or sexual arousal.

Breasts are unique, and it’s perfectly OK that they have their own distinctive shape and size.

The only thing that isn’t normal is unexplained pain and sensitivity.

A few factors can determine why your breasts are the way they are.

Genetics have the biggest say, by far. Your genes influence your breast density, tissue, size, and more.

Other factors that shape your breasts include:

Weight. Fat is a large part of your breast tissue and density, so you may notice a difference in your breast shape as you gain or lose weight.

Exercise. Your breasts might look firmer or perkier if you build up the muscles behind your breast tissue by strengthening your pecs.

Age. Your breasts will naturally sag as you get older, so over time, your breasts may become longer and shift to face downward.

Pregnancy and breastfeeding. Your hormones during pregnancy and breastfeeding can make your breasts swell and change the way the fat and tissue are distributed throughout your breasts.

Everyone has their own unique breast shape and size. Some people have made up classifications of breast shapes, but all of them are based on visual appearance. There is no official or medical classification for breast shape.