Taylor remains champion following two judges scoring the bout 97-93 in her favour while a third ruled it even at 95-95.
The 10-round fight at Madison Square Garden was streamed live on Netflix and headlined an all-women's card in New York.
"I don't know, I just don't want to fight Amanda Serrano again," Taylor said following her win.
"I have a huge ton of respect for Amanda, she's such a warrior. It was a pleasure to share a ring with her.
"We have made history three times; we are history makers forever."
The Irishwoman has now won 25 fights and lost just once in her career, while Serrano now has four career losses - three of them coming against Taylor.
On the undercard, several British fighters were featured with Savannah Marshall handed a shock loss by Shadasia Green, while Ellie Scotney defeated Yamileth Mercado and Chantelle Cameron recorded a unanimous decision win over Jessica Camara.