Let me just start by saying the female body is truly incredible. During a woman’s lifetime, she can help create a child, grow a child, birth a child, and feed a child, all just with her body.

Part of this body is her breasts. Shown from the beginning of time in famous art pieces where Madonnas are seen nursing their little ones, to causing major controversy with nursing in public. Being seen as sexual objects in our media, to being the symbol of femininity and beauty. And of course, to providing the ultimate magical food for our babies, breasts are a BIG topic.

Here are 22 facts that are often understated, unknown, or misunderstood about breasts and why they are so interesting and amazing (in case you didn’t already feel this way):

1. The word mammary comes from the Latin and Greek term for breasts, mamma which was developed from the infant’s hunger cry sounding like “mamma.”

2. Your breasts change and develop through life starting in-utero, to puberty, to pregnancy, to breastfeeding, to weaning, after weaning and menopause. No other organ in the body goes through such dramatic changes in shape, size, and function.

3. Your breasts can make breast milk that feeds and sustains your baby totally and completely without any other substance for its first 6 months of life. What is more amazing than that!? Plus, breastmilk has a double function providing your babe with nutrients and defense against infectious agents. All of the defenses protect without causing inflammation in the baby.

4. Human breasts differ from all other primates’ breasts as they grow long before pregnancy, during adolescence, and even after weaning. Other mammals’ breasts only grow during lactation and flatten down when their young have been weaned.

5. Your nipples and areola increase in size and become darker while pregnant in preparation for your little one who has poor eyesight at birth—they can only see about 8-12 inches away, which is perfect viewing distance to their mama’s face while nursing.

6. You have small bumps on your nipples called montgomery tubercles that greatly increase in size during pregnancy to help your baby locate your nipples and help to condition, cleanse and lubricate your nipples for breastfeeding. This fluid provides sensory stimulation so your babe will instinctively move toward your breast at birth.

7. Your breast tissue reaches all the way up to your armpit, and this area is called the tail of spence. You may even get breast milk in your armpit. Make sure this tissue is not forgotten when checking for cancerous lumps in self exams and with your OB/GYN and for painful plugged ducts during nursing that could turn into mastitis.

8. Each woman has differing numbers of ductal openings on their nipples where the milk exits the breast to the baby. Depending on the woman, she can have anywhere from 4-18 in each breast.

9. Even though breasts are considered sexual, your mammary glands are not part of the reproductive system. These glands are a type of secretion gland, a mucous membrane, which is why you should not take any kind of decongestant medication that will dry up your mucous membranes while breastfeeding.

10. The average breast weight is 150-200g. During lactation, this number more than doubles to 400-500g. That means the breasts gain at about a POUND during lactation!

11. There is a nerve (the 4th intercostal nerve) that enters the back of each of your breasts (left breast is 4:00 and right breast is 8:00). When the infant is suckling, this nerve is stimulated, triggering your brain to make more milk. When plastic (from a pump, for example), is in between the baby lips and the nerve, there will be less stimulation, contributing to less output of milk seen with pumping.

12. Breast asymmetry is common—the left breast is often larger than the right.

13. Lactogenesis is the transition your breasts make from pregnancy to lactation. Once you’ve delivered your placenta, you have a rapid drop in the hormones progesterone and estrogen, telling your body you are no longer pregnant. With the help of a few additional hormones, your milk production begins and it creates the exact amount and exact formula your baby needs in colostrum.

Colostrum coats the baby’s entire gut (mouth to anus) to protect it from any outside bacteria and is filled with amazing-ness to protect and nourish your brand new babe.

Lactogensis II is the start of copious milk secretion controlled by your hormones, beginning between day three and day five. Your milk will “come in” regardless of emptying within the first few days after birth because it is hormonally driven.

After Lactogenesis II, you move into autocrine control. This is where your breast milk production works by milk removal—supply and demand. When your babe nurses, fully and frequently emptying your breasts, there is a feedback mechanism that tells your brain to make more milk.

An empty breast tells your body to make more, while a full breast will tell it to slow down. Your milk supply changes all the way until you wean, including changes in composition, depending on what your baby’s needs are.

As long as milk is removed, your breasts will continue to make milk indefinitely.

14. You can re-lactate (re-stimulate lactation) weeks, months and even years after having your child. It takes serious commitment, and you may not establish a full supply again, but your breasts remember. Adoptive parents who have never nursed a baby before can induce lactation, in a similar way to re-lactation.

15. Has your baby ever pulled off while you are having a letdown and you shoot milk across the room? Your milk ejection reflex is in response to suckling, and the hormone Oxytocin causes this reflex to occur. This can feel like burning, aching, a warm sensation, pressure, or tingling down your breast. In most women, their first letdown occurs around two minutes after the baby latches and you can have multiple milk ejections during a single feeding.

16. Size doesn’t matter. The size of your breast does not tell you how much milk you will be able to make. What it can tell you is how much milk you can store in your breast at a time. Women with smaller breasts may have to do more frequent feedings, both day and night.

17. Your breasts are never fully empty. An infant takes about 2/3 of the milk out of your breast at a feeding.

18. Breastfeeding will not cause your breasts to sag! Breastfeeding does not actually change the way your breasts look. The changes come from being pregnant. But please try not to worry—although your weaned breasts may look saggy, in time (around six months plus), fatty tissues do come back to some extent and your breasts will look more like your pre-pregnancy breasts (woohoo!). Genetics, skin elasticity, smoking, your age, and weight gain in pregnancy will however, effect this.

19. Around the world, even in third world countries, breastmilk composition remains stable. Unless a mother is severely malnourished, her milk volume and quality is not affected by her nutritional status.

20. Scientists are hypothesizing that when your infant is sick, through saliva transfer (ahem, backwash) back into the breast, your milk will adjust its components to fight off exactly what your little one is fighting.

21. Some women can reach orgasm from breast and nipple stimulation alone. Through a study done in the Journal of Sexual Medicine, nipple stimulation did affect the genital sensing brain areas.

22. If you need some help going into labor, try stimulating your nipples! Nipple stimulation causes Oxytocin to be released which will then cause uterine contractions.

And finally, to add the all this awesomeness, breasts are beautiful, cozy pillows for your little babies or your partners to snuggle on, ask anyone 🙂