One of the greatest myths since the invention of brasseries is that your boobs are unlikely to change in size during your adult life.
Truth be told, there are several factors that can affect your bra size (and we’re not talking about cosmetic procedures). That’s why it’s so important to check that you’re wearing the right bra size regularly. Here are four frequent factors that can affect your bra size over time.
Apart from experiencing tenderness and soreness, menstruation or birth control can cause your breasts to get bigger. This is all related to the hormones your body releases during the menstrual cycle. Higher levels of estrogen cause the breast ducts to swell and, in turn, you can develop a fuller and larger bust.
Whilst the size of your breasts is mostly determined by genetics, your body-fat percentage also plays a role. Fat is the main component of breast tissue, so the higher your percentage of fat, the denser your breast tissue will be. That's why a recent fat loss or gain will likely coincide with a change in cup size. The more you know!
Pregnancy or Breastfeeding
The human body undergoes many changes during pregnancy, as your blood volume and body expands to meet the demands of your growing features. Women can go up an entire cup size by the time their pregnancy reaches six weeks. Once you start breastfeeding, your breasts can continue to enlarge as they begin to produce milk, and can even increase two to three times in size during this period.
If you’ve been hitting the gym recently and you’ve noticed that your boobs look a bit fuller, it could be all those chest exercises! Your pectoral muscles lie just underneath your breast tissue and various exercises—such as bear crawls or push-ups—can help strengthen this area of the body. A regular workout can make your boobs perkier and fuller, so much so that you may even have to purchase a new bra to accommodate.
Your bra size could even differ across lingerie brands, so don’t feel confused if you’re a size 10B in one store and a 12B in another. It’s important to always check that you have the right bra size so that your boobies are feeling well supported.
If you’ve noticed a change in your bra size, take this as an opportunity to restock your underwear drawer. There’s no reason why you shouldn’t treat yourself to a great new piece of lingerie. 
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