By JEFFREY ZASLOW
online.wsj.com
In the days ahead, Alicia Gaudio will be visited by a woman she has never met to receive a gift she wishes she wouldn’t need.

Mimi Ritzen Crawford for The Wall Street Journal
Nicole Rowe, holding the wig she wore during cancer treatment, with her husband Michael, daughter Jordan and son Alex. She is giving the wig to Alicia Gaudio.

Ms. Gaudio, who is 23 weeks pregnant, learned two weeks ago that she has breast cancer. On Thursday, the 40-year-old attorney from Mt. Kisco, N.Y., underwent a mastectomy, which will be followed by …