Scarleteen

I seem to have lost a cup size in just the last couple weeks. My weight has not changed - I've been slightly underweight for over a year now, maybe two - and I'm not exercising more than usual (my exercise consists of walking around on my very hilly campus and going dancing once or twice a week, less than activity than during this past summer). I'm eating sporadically, but that's fairly typical for my habits for the last few years. I switched from the Nexplanon implant to the Skyla IUD about three months ago; my breasts were very swollen on Nexplanon (that's why I switched), but as soon as I moved to Skyla the excessive swelling stopped and until recently I'd gone back to my normal size of 32D/DD (the size I've been since before I started any BC and maintained while on my first BC, Depo Provera). I noticed the issue because I handle my breasts fairly often; they usually overfill my hands, but currently they fit in them. I went so far as to find a measuring tape and take my measurements, which I've kept up with for a few years now; my waist and hip measurements have not changed, but I've lost two inches in my bust since the last time I measured myself (sometime this past summer).

Has anyone experienced something similar?

It's fairly common to continue having some breast changes throughout puberty and into the 20s, and, in different ways, throughout a whole life. It wouldn't be surprising if your breasts were a little different now than they were before you started any hormonal birth control.

Too, bodies usually don't distribute fat, or gain and lose fat, uniformly evenly all over. It's not uncommon for someone with breasts to lose a little fat off the breasts before anywhere else, and especially if you're fairly active and not always eating regularly, it's possible that's what happened here, on top of the effect of switching off hormonal birth control.

Let me clarify:

1. I've been a 32D/DD since freshman or sophomore year of high school, so that's going on seven years. Even when I lost ten pounds freshman year of college because of my sporadic eating habits, my breasts did not change in size. My entire body has been very consistent in terms of weight (ignoring the recent loss) and measurements for the past seven years or so; I have "always" been roughly 125 lbs (114ish now), and a 35-25-36.
2. I'm still on a hormonal birth control - the Skyla IUD. I maintained a 32D/DD on my first BC, Depo Provera, which I started as a college freshman three years ago and was on until January of this year. I was briefly on Nexplanon (mid Jan to mid June of this year), but that caused prolonged breast swelling and eventually severe tenderness/pain, so I switched to Skyla. After I switched to Skyla, the swelling stopped and I went back to 32D/DD within a couple weeks. I stayed at 32D/DD until just recently.
3. My breasts shrank at least one cup size in the last couple weeks, at most, despite a decrease in activity and minimal change in calories consumed.

I have an appointment Monday for a different issue, but I'm going to try to address this instead. The suddenness of the change concerns me.

It sounds like checking in with your doctor is a good idea, if only to give you some peace of mind. Going down a cup size is a pretty significant change to happen in just a couple of weeks, and while it's still entirely possible that this is just a bit of weight loss or hormonal changes, it never hurts to double check.

(Also, a hormonal IUD like Skyla isn't, primarily, a hormonal method. The hormone it contains is a small amount of localized hormone to counteract some common side-effects of an IUD; that hormone isn't really a part of how it works as a contraceptive method. So, the vast majority of people won't experience anything like the same kinds of effects in the rest of their bodies that they do or would from hormonal methods of contraception.)