A rep for the Guys with Kids actress spoke to the news source, saying, "Everyone is happy and healthy."
Sigler, 32, and her fiancé, baseball player Cutter Dykstra, became engaged in January and announced the pregnancy in February.
The former Sopranos star spoke to ET during her third trimester in June, saying that with other friends recently becoming moms, her pregnancy came right on time.
"It's such a blessing to go through this with your friends and to call each other for questions, and the fact that I am last [means] they'll all have a couple of months on me," said Sigler, whose celebrity friends Jenna Dewan-Tatum and JoAnna Garcia Swisher both gave birth in May. "It will be good to get their advice."