29 weeks pregnant. for the first time my nipples began leaking. one leaked brownish liquid. should i be concerned.

Colostrum is normal: The leakage of clear to white or yellow tinged fluid from the breasts during pregnancy is colostrum. In my experience about half of women will have this during pregnancy and the rest only notice it after delivery. If it is brown that might be a little blood which rarely can be associated with a growth in the breast. Speak with your doctor about this.

See Dr.: Nipple drainage during pregnancy is not "uncommon." brown colored liquid should be discussed with your gyn and a good examination and close follow-up should be fine to assure all is well. Good luck.