Q&A: Is a small breast lump in the fifth month of pregnancy normal?

Pregnancy is just the party the breasts have been waiting for all their lives. Prolactin (the milk let-down hormone) rises, and it's not unusual for lactation to begin even before delivery, which is weird but normal. Since the breasts are collections of glands that make milk, it's not unusual for a milk duct to get engorged during all of this stimulation. This can be quite normal.

There is, however, the possibility that a breast lesion, which would normally not be felt, is pushed to a more prominent and noticeable status by the thickening of underlying breast tissue. Admittedly, it may be impossible to tell the difference. The criteria for suspicious breast lumps apply whether or not a woman is pregnant.

Breast lumps that are not suspicious have the following characteristics:

• Freely moveable (cancers tend to invade, and therefore feel stuck to the surrounding tissue).
• Painful, which usually means inflammation, not tumor.
• Vascillations of size (cysts related to milk production will change size with the ups and downs of the hormonal fluctuations. Bad cysts will stay the same size or grow bigger).
• Very round-ish. (Malignancies are irregularly shaped.)
• Small size (less than a centimeter is small.)
• Suspicious breast lumps show the opposite of 1-5 above.

Usually an obstetrician, being also a gynecologist, can help assign any suspicions to a lump. If he or she is uncomfortable with making a diagnosis, then a second opinion from a general surgeon can help finalize the call. Chances are it's nothing.

But we should respect the breasts, both for the life they provide to a suckling infant, and for the disease they can incur when cancerous. When in doubt, overreact. A mammogram usually involves less than 10 mrads. of radiation. And doses below 5,000 mrads. do not carry any significant risk of fetal injury.

Even with this safety margin, go with your OB on this one. If he or she thinks it's nothing to worry about, it's probably not worth a mammogram.