As rumors about Gwen Stefani and Blake Shelton’s wedding continue to grow, a new report by Life & Style magazine Thursday said that the couple is trying to have a baby. The mother of three boys is planning to undergo in vitro fertilization, the report added.

"It’s only a matter of time until they formally announce the engagement,” a source told Life & Style. “And while they’re planning the wedding, they’re actively trying to start a family. They’ve never been happier or more in love.”

The 46-year-old has already looked into all options, the report said.

“She has incredible doctors and she’s explored all her options, including surrogates,” another source told the magazine. “No matter what, Gwen wants the child to be hers and Blake’s baby together. She’s ready.”

Rumors about Stefani and Shelton’s wedding have been doing the rounds lately. The couple is reportedly planning to exchange vows during Christmas and Stefani’s children are rumored to be an important part of the wedding. The couple, however, has not commented on the reports or the rumors.

Recently, In Touch Weekly magazine reported that Shelton and Stefani are having differences over where they should settle down after getting married. According to the report, Shelton has no plans to live in Los Angeles permanently and Stefani “feels she could never ditch California and live in Oklahoma as a full-time resident” as she prefers to stay on the West Coast. She also reportedly does not want to take her children away from their dad Gavin Rossdale, In Touch Weekly said.