LOS ANGELES—Given that Hollywood has had a difficult time turning great books into movies that have satisfied readers, you probably would be reluctant to let your self-help book be transformed into a romantic comedy. This would be particularly true if the book had sold more than 15 million copies and was still in print. Would an unsuccessful movie turn away potential readers?

What to Expect When You’re Expecting author Heidi Murkoff was so concerned about readers’ expectations for a film version of Expecting that she spent years turning down lucrative offers for the rights to the book, which was written in 1985. In a Los Angeles hotel room, she says she was reluctant to have the book she wrote during her first pregnancy made into a movie, despite the many offers that were made.

“I had been dragged kicking and screaming to every pitch meeting. I have a very challenging gut, and when I run something through the gut test, I rarely approve. I also didn’t think we [she and her husband, Erik] would have a high level of participation, and I feel I have a responsibility to the readers. It is Hollywood, so there is never complete control or anything approaching that. But we were given executive-producing credits, and I had lots of input into the making of the movie.”

The movie opens May 17 and features stories about five couples preparing to deal with parenthood. It stars Jennifer Lopez, Cameron Diaz, and Glee’s Matthew Morrison. Murkoff says that although she wanted the moms to be strong, she was concerned that if she didn’t participate fully, it would be the fathers who would be the victims.

“Dads have been terribly bashed by the media. And in commercials, it is always the father who is the bumbling idiot. I think the media don’t give them a chance, so it was important to me to make sure that there was nothing mean-spirited.”

The film’s director, Kirk Jones, says he saw potential in the book but only really embraced the idea of making the movie when he saw the completed script from screenwriter Shauna Cross. “I thought this could be a strong concept for a movie, and I wasn’t concerned about the fact that it was inspired by a self-help book. I felt that the script had made the five stories work while keeping key elements of the book strong. Interweaving the stories together was the challenge, and I think we did a good job of that.”

Although she admits that she was reluctant to take a book designed to help parents cope with pregnancy and turn it into a romantic comedy, Murkoff now feels that it worked out for the best. “It sounds random to turn a how-to guide into a romantic comedy, but what is more romantic than starting a family together? And what pregnancy doesn’t have humour? It has all the elements of comedy, and it is certainly relatable. You laugh and cry and, hopefully, you walk away from the film feeling good.”

Watch the trailer for What to Expect When You’re Expecting.