Would breast cancer have increased in size in 6 months? i'm pregnant, 28 years old. had ultrasound that showed no change in area from six months ago.

Yes, most likely: It is unlike that a lump is cancer if it has not grown at all in 6 months, although some breast cancers do grow very slowly. It is difficult to evaluate breast lumps by physical exam as pregnancy progresses because the breasts become engorged. Ultrasound is a good method of following the lump but i defer to your physician to decide whether or not excision should be considered.

See a doctor: This is most likely a noncancerous lump. I recommend finding a breast specialist in your area who can examine you and review your films. If you have concerns, a needle biopsy can be performed.