During pregnancy, what makes your breasts increase in size?

Hormonal Maturation. Actually a complicated answer. Starts at puberty->E2 causes a system of breast ducts to develop, then secretory glands that will store the milk develop by your first period & then group into sets of lobules. Each cycle progest causes these to enlarge (monthly breast pain), if no preg->back to nl. If preg E2/progest ?->matures ducts/glands/lobules. FSH,LH,Prolactin,oxytocin,HPL->milk prod->? size.

Related Questions

Other than at the tym of pregnancy, when & how can d size of breast increased?

Breast augmentation . The only effective way to alter breast size and shape is through surgery. Save your money. Pills and creams advertised on the internet are scams. See a plastic surgeon. Read more...

My breast didn't grow at all during pregnancy. Most of my friends went up cup sizes. Is this because I don't have much breast tissue?

Possible. Growth of breast tissue depends on how many cells all responsive to the hormone available. Not to worry you can always augment to breast at a later time if you want to. Read more...