You watched your mammaries explode into gigantic Kimmie Kardashian-sized orbs, saw them squirt milk like a cow, and wondered why they shrunk even smaller when all the excitement was over. (Hey, even supermodel Gisele Bundchen reportedly snuck into a plastic surgeon’s office to revive her own deflated post-pregnancy pair after having her second child.) Here’s a look at some of the wild things that birthing babies can do your chest—and what you can do about them.

Your girls go south

Turns out pregnancy is the culprit, not breastfeeding: A study published in the Aesthetic Surgery Journal found that there’s no more ptosis (that’s a la-dee-da name for breast sagging) among moms who nurse than those who don’t. “When you gain weight during pregnancy, ligaments in your breasts stretch, just as they do in your abdomen,” explains Fahimeh Sasan, DO, assistant professor of obstetrics and gynecology at the Icahn School of Medicine at Mount Sinai in New York City. Alas, you don’t have that much control over a droopy bosom; how well these ligaments rebound can be credited to—or blamed on—your genes. Yet limiting the amount of weight you gain and lose may minimize sinkage. And yes, you could always have a breast lift.

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You get marks on your mammaries

It makes sense—all that stretching that occurs during pregnancy and breastfeeding also causes the collagen and elastin in your skin to expand. “A lot of this boils down to genetics, so if your mom or your sister didn’t get stretch marks, chances are you won’t either,” assures Dr. Sasan. If you didn't win the good-gene lottery, you may have to wear your stripes with pride: Slathering on vitamin E oil or cocoa butter should make the skin feel more supple, but that's about it. Stretch marks still pink? You may be in luck. Applying an Rx topical retinoid like Retin A at this early stage can stimulate collagen growth, helping to plump out skin.

One boob’s bigger than the other

Nope, you’re not just sleep deprived: Ending up with asymmetrical breasts after your kids have nursed is totally a thing. “The breast the baby prefers naturally stretches out, as can the nipple,” says Dr. Sasan (that’s why nipples may look bigger or elongated even after you’ve weaned). Most of the time, the size discrepancy is so subtle that it’s barely noticeable. But if it bothers you, consider switching to padded bras with removable pads so you can use them on one side. And if you just can't make peace with the size mismatch? Cosmetic surgery is an option—either a breast reduction on one side, or a small implant on the other.

RELATED: 4 Exercises to Perk Up Your Boobs

Someone's baby cries, your breasts leak

If you're breastfeeding, you've probably noticed that any ole baby will trigger your let-down reflex and cause your milk to flow. Even just daydreaming about your baby can open the floodgates, according to the U.S. Department of Health and Human Services. Other offbeat stimuli include newborn baby smell, running water, and sex.

They growor shrink

Your breasts may or may not return to their pre-pregnancy size and shape. “Some women’s stay large, and others shrink,” says Karen Soika, MD, a cosmetic surgeon in Greenwich, Connecticut. This is due to a confluence of factors, including genetics, whether or not you’re still holding onto a few new-mom pounds, and your age (younger women tend to have denser breasts, which are less affected by weight fluctuations).

RELATED: 5 Things You Really Shouldn't Be Doing to Your Breasts

Your breasts become less dense

With every pregnancy, breast density tends to go down, explains Dr. Soika. While your pair may be fattier and more prone to sagging post-kids, there is a great silver lining: a lower risk of breast cancer.