Why do your breasts swell during your term? (women only)?

Ive been wondering this for some time presently.. why do they swell up and hurt?
Answers:

Some of it is retaining water when you menstruate and the other sector of it is hormones. Your hormones change throughout your cycle ALL month.

Im on birth control & my time has changed from brown to clear?

its in recent times your hormons are all crazzy

I enjoy what seems to be a pulled muscle on my right breast?

so if i be an ob/gyn i couldnt answer this question?
p.s. im a guy.

Discharge..?

Hormones call prostaglandins are the culprit. They are also responsible for the cramps and over all crappy ambience you experience during your cycle.

Women thing?

As you in the vicinity your period, hormones are building up in your body, which can rationale the breast tissues to swell. If you don't lower your sodium intake at this time, you'll find that your breasts become really sore, due to the water retention. Just shrink your sodium intake, and you will notice a huge difference

Will it affect by any adjectives to child birth after my marriage?

Incresase contained by estrogen levels and your also retaining marine.