Post-pubescent breast growth?
January 15, 2013 3:08 PM   Subscribe

Why would a mid-twenties woman's breasts suddenly grow, if unrelated to birth control or pregnancy?

My girlfriend (who lives overseas) recently arrived to stay with me for three months. In the one month that she's been here, her breasts have grown from roughly a B cup to a large C cup. They're feeling tender and a little sore sometimes.

She's not on any hormonal birth control, and had a period two weeks ago, so it's not related to pregnancy.

Our only theory is that since we're usually apart, and this is the first time in many months that she's been having sex so frequently, perhaps there's something hormonal going on that's causing her breasts to grow. That being said, we've been apart before and when we met up this hasn't happened then.

Is this something we should be worried about? Are they likely to return to their previous size at any point? Are they likely to continue growing? Any advice is much appreciated.
posted by twirlypen to Health & Fitness (32 answers total) 6 users marked this as a favorite
Diet or alcohol intake changed since she's been there? That would be my first guess.
posted by efalk at 3:10 PM on January 15, 2013

Can also be caused by weight gain.
posted by dottiechang at 3:10 PM on January 15, 2013 [2 favorites]

and had a period two weeks ago, so it's not related to pregnancy

These 2 things are not related. Women can have a period after conceiving. If you aren't using proper protection, that is actually the most likely answer.
posted by DoubleLune at 3:10 PM on January 15, 2013 [28 favorites]

She should definitely take a pregnancy test if she has not already.
posted by something something at 3:11 PM on January 15, 2013 [16 favorites]

3rding that it's time to pee on a stick.
posted by DarlingBri at 3:20 PM on January 15, 2013 [4 favorites]

If the test is negative take a second, they're cheap. If they're both negative, see a doctor, because rapid hormonal changes are often a sign of something not being cool and froody.
posted by elizardbits at 3:22 PM on January 15, 2013 [6 favorites]

In general, sexual activity doesn't have a marked effect on hormone production. It could be bloat from jet lag, and it could be a messed up period schedule from jet lag (it does horrible things to me) and she's about to have a period again. It could be brain tumor, thyroid condition, or maybe you're having such enthusiastic playtimes that she's actually getting hurt.

But the Ladies Rule of Thumb is: if your boobs hurt, take a pregnancy test. If they still hurt in three days with no sign of a period, take another. If they're both negative, go to a doctor to see what else it is.
posted by Lyn Never at 3:24 PM on January 15, 2013 [2 favorites]

Definitely pregnancy test.
posted by hrj at 3:27 PM on January 15, 2013

FWIW, mine grew about the same age. An exbf I ran into would not believe I didn't have implants.

So of course be sure nothing is going on - but randomly getting boobs at that age does happen.
posted by crankyrogalsky at 3:55 PM on January 15, 2013 [3 favorites]

This happened to me right around the same age. I went from president of the Itty Bitty Titty Comittee to suddenly having to worry about wearing deep v necklines at work, button-down shirts gaping, whether a given bra would be supportive enough, and all the other annoying things women deal with, chestwise.

Bodies are weird. In retrospect I refer to this physical change as "when I finally went through puberty".
posted by Sara C. at 4:17 PM on January 15, 2013 [1 favorite]

Haaaa my boobs grew about a cup size when I was briefly pregnant. It was about a month from conception to full onslaught boobage. Also, I had a "period" at the same time. I was still pregnant.

It's always possible she's having some kind of spurt, but that's awfully fast for a spurt. If she's not pregnant and hasn't gained weight, she might want to run this by a doctor to make sure something else isn't afoot.
posted by Coatlicue at 4:21 PM on January 15, 2013 [2 favorites]

The only time I have ever heard of someone gaining that much in their top-regions in that short a tie span was either pregnancy OR some sort of hormonal disorder. So I recommend peeing on a stick first, and a clinic visit second.

Also, my mom had a period (well, I suppose it's just spotting that resembles a period) for about half of her pregnancy with me. I wouldn't be using the fact that your girlfriend has recently had a period as a gospel for anything.
posted by sm1tten at 4:29 PM on January 15, 2013 [1 favorite]

Your choices are basically: weight gain (or increase in bodyfat %), pregnancy or some weird hormonal thing.

You might want to Google implantation bleeding too.
posted by fshgrl at 4:43 PM on January 15, 2013

Sounds mighty pregnant, but could just be late growth. Like everyone else says: take tests, see doctor, don't worry
posted by mumimor at 4:47 PM on January 15, 2013

Response by poster: Thanks all - the reason I presumed it wasn't pregnancy is that the growth started before the period, so any potential conception since then wouldn't explain the start of it.

But yes, it could have been a false period after pregnancy... I'll get a test today.

There's been no noticeable weight gain anywhere else. I'm very certain she wouldn't know her body weight accurately enough to know if there's been any gain (she has a slim build, any significant gain would have been visible elsewhere I'd have thought).
posted by twirlypen at 5:07 PM on January 15, 2013

Yeah my boobs grew from a solid almost-A to a solid almost-B when I was about 22 or 23, with no real explanation. I also got an ass overnight. There wasn't so much weight-gain as there was weight-shift from one place to another.
posted by greta simone at 5:09 PM on January 15, 2013

There's been no noticeable weight gain anywhere else.

As the voice of "maybe it's nothing", I'll say that, when this happened to me, it didn't come with overall weight gain. It was more that the way I carried weight changed. It used to be that I would mostly carry weight in my hip/butt/thigh area, and was noticeably pear shaped. Something happened in my mid 20's and I became a little more hourglass shaped.

Then again for all I know I am now dying of thyroid cancer due to my mid 20's growth spurt. I generally agree with folks that a doctor visit is in the cards.
posted by Sara C. at 5:13 PM on January 15, 2013

Growth spurts can happen in all sorts of ways and it's pretty common for a woman to have another one in their 20s. I did, and most of the growth was in my breasts (but my breasts, it seems, just keep on growing, like noses and ears or something... but that's me, I'm idiosyncratic in this way, your GF is idiosyncratic in other ways I'm sure) as well as my feet, and more importantly to me, in my hips, thank goodness. This happened when I was about 24, but I have friends who have had this happen as late as their early 30s. It's normal to feel tender and little sore, simply because growing hurts no matter when it happens. But yes, definitely check for pregnancy, and if anything gets really painful (like, your GF has probably had bloating and breast tenderness due to menstruation at some point, and if it's worse than that) a doctor's visit seems conscientious. I've definitely experienced a full cup-size increase in breast size during particularly wacky menstrual cycles, and they've gone back to "normal" after I've taken better care of myself and things have hormonally evened out. But if this is unusual for your GF, and if she's listening to her body and it's basically saying "abort abort! something is up!" then yes, doctor and test time. Everybody's different.
posted by Mizu at 5:49 PM on January 15, 2013

This sounds like my first pregnancy to include the period. Time to pee on the stick.
posted by St. Alia of the Bunnies at 6:47 PM on January 15, 2013

I think it's lots of sex and stimulation of her breasts. I've experienced larger breasts when having vastly more sex than I was used to before. (In this situation, there was zero chance of pregnancy.)
posted by 3491again at 8:01 PM on January 15, 2013

I would recommend doing a pregnancy test at a clinic, not at home, since they can give you much more accurate counseling and assessment re pregnancy risk than we internet strangers can. Additionally, they may also be able to do a blood test as a second option if they think it is appropriate. (Pee-on-a-stick tests at home are about as accurate as clinic tests; but neither gives you an accurate result until 10 days after possible risk.) So, if there's been any semen anywhere in her vagina and it's been less than 10 days since that jizzposure, you could get a false negative. Make sense? Looks like these clinics have walk-in testing:

Also, and unrelated, I, too, had a sudden boob growth at about 26 or 27 years old. Went from being a B cup to a D/DD. (I'm not complaining.) Nothing else really changed simultaneously, though I did end up gaining weight *after* the sudden boob growth.
posted by Betty's Table at 8:29 PM on January 15, 2013 [1 favorite]

Diet change can absolutely do this. When I did the Whole 30 my boobs went up a cup size despite losing ten pounds, and they'd never been that big even when I weighed 50 pounds more. It took two weeks to be obvious, then a month was super obvious and I had to buy new bras. Food has a huge impact on hormones.

If she was overseas and came to visit, she's probably not eating the same stuff she usually does.
posted by Nattie at 8:56 PM on January 15, 2013 [1 favorite]

If she's visiting you she's probably doing a lot more sitting around and generally relaxing. I will gain weight in my boobs before any other part of my body and a month of taking it easy would definitely make me gain weight.

I think this is why a lot of women get boobs and a butt in their mid 20s, they get their first office job and lose muscle/ gain fat and on most women, that's where it goes. I weigh what I did in college but I was all muscle then. Now I'm... not.
posted by fshgrl at 9:42 PM on January 15, 2013

If it isn't pregnancy, weight gain, or major diet changes, something Bad could be going on, she should probably see a doctor regardless.
posted by Slackermagee at 10:21 PM on January 15, 2013

She should indeed pee on a stick and see a doctor, but for what it's worth I go up and down at least half-a-cup-size regularly as part of my cycle and - because I am middle-aged - whenever I eat too much salt. (I used to think I was maybe a were-camel except that I ruined it for myself by reading that camels don't actually store water in their humps. Now I have no excuse for braying and spitting on people when my breasts hurt.)
posted by gingerest at 10:56 PM on January 15, 2013 [2 favorites]

A lot of women, really most, experience a significant shift in metabolism/other body stuff right around 30ish, give or take a few years. My pants and shirts still fit, but I didn't notice at first. In retrospect, I did get more attention and filled out my clothes a little more, but it was gradual.

Eventually I figured out that I bumped up from a B to a C around that time. Also, I bruised myself for a couple of years by banging into pretty much anything within a foot of me until I figured out that my skinny-ass self had sprouted hips.

Sure, regular checkup as always, especially if her breasts are more tender than usual. But it might just be an odd little hormonal shift.
posted by desuetude at 12:05 AM on January 16, 2013

Mid-twenties could still be the last burst of puberty. It normally happens in the very late teens/early twenties (which a lot of people don't know, they think you're done by 16 or whatever) but eh, bodies are weird.

It could also be weight gain that just happens to hit there first.

The other thing a lot of people don't know is that the composition of breast tissue changes in a cyclical manner across the menstrual cycle, with the balance between ductal tissue and fatty tissue see-sawing in time with hormonal changes. So it could still be hormonal and normal. Personally my breasts get somewhat larger and very tender for some days ending three days or so before my period, a pattern that only started in my late twenties, and I'm totally healthy.

And yeah, she could be pregnant so do a test to be sure.
posted by shelleycat at 12:43 AM on January 16, 2013

Does she take any vitamins or minerals? I took MSM for joint pain, hair growth, and nail growth. I got slightly larger breasts. Same with evening primrose oil. (They're both used by Natural Breast Enhancement people for that purpose.)
posted by Ms. Moonlight at 3:59 AM on January 16, 2013

I shot up a cup size literally overnight at about 23. Went to a gaming night at a friends place, slept in my shirt with the bra off, and presto! Bra didn't fit in the morning. Happened to my sister, too.

Really do get your pregnancy test, because if she's not on any hormonal birth control and you've been having catch up sex, there's an awful lot of room for extra fertility there. But honestly it's unlikely to be Death Cancer of All the Places if she has just finally finished the last bits of puberty.
posted by Jilder at 4:23 AM on January 16, 2013

This happened to a friend in school, who came over from Germany to do research in the US. She blamed it on hormones in the milk; I don't remember if she started only drinking organic non-hormone milk or not, but she was fairly freaked out.
posted by aimedwander at 9:14 AM on January 16, 2013

just chiming in with whoever upthread mentioned something similar happened to them at that age and they never did find a real reason. when I was 27 or so, i went through a bizarre "second puberty" where i went up a buncha cup sizes and got a little bit of hip (i'd always been straight-up-and-down prior). my husband noticed it right away. i wasn't pregnant and nothing was wrong. it can just happen sometimes, not to say it's not a good idea to rule out any medical problems, just, it is possible she's ok too.
posted by ifjuly at 1:08 PM on January 16, 2013

That early-mid twenties body change also happened to some of my friends and I. And it's been noticed that frequent massaging increases the size of breasts too.
posted by proximacentauri at 6:45 PM on January 16, 2013

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