Swift, 24, visited Stephanie Barnett, who lives in Connecticut. Barnett said Swift's music had helped her through the emotional time when she was having trouble getting pregnant.
The Grammy-winner got gifts for Barnett's two-year-old son, Leyton, reported E! Online.
"I open the door and she's like, 'Hey, Steph!' and it's just her right there, and I lost it. I lost it for a while," Barnett said.
One of the gifts included a toddler-sized toy Mercedes for Leyton, who wouldn't leave her side.