Ironically, the day that preview performances begin for the Purple Rose Theatre’s world premiere production of “Some Couples May … “ — which focuses on a couple struggling with infertility — playwright Carey Crim is due to give birth to her first child.

The play is not reflective of Crim’s own experience. But between friends who were struggling to find a way to bring a child into their lives, and Crim and her husband’s own discussions about whether or not to become parents, the seed was, well, planted.

“People always think that it’s about establishing your career first — that that’s why you wait to have kids,” said Crim. “But for a lot of people, you just don’t meet person you want to have kids with until you’re older. Besides, you can be 31 and have trouble, too.”

In the play, an event planner and her pediatrician husband have a wonderful, loving relationship, but the two struggle for two years to become pregnant before exploring in-vitro fertilization. Meanwhile, the husband’s brother and his wife are expecting their fourth child, despite the fact that the woman is 44.

“I think (reproduction) is one of those things that people take for granted, like space flight,” said director Guy Sanville. “But once you’re into it, you realize how much is involved, and there’s nothing easy about it. Everything has to go a certain way.”

Perhaps fittingly, “Some Couples May … “ began life with a bit of a false positive. The play Crim originally brought in for a greenhouse reading at the Chelsea District Library was called “The Third Day,” and it focused on infidelity.

Sanville was reading/hearing it for the first time at a table reading when, early on, Crim’s face revealed her own dissatisfaction with the script.

“I’d had reservations about it long before,” said Crim. “Nothing about it seemed to flow. … It was a struggle from start to finish, yet I stubbornly worked on it longer than any play to date. There’d been other readings, … and they went pretty well, but it never felt quite right. It never felt true to me.”

At the table reading, Sanville called for a break to find out what was bothering Crim, at which point she confessed to hating the play. So although the two knew they needed to present something at a staged reading only days later, what remained of the reading was canceled, and Crim left to start writing something else entirely, based on the kernel of an idea.

You might think Sanville would worry about this turn of events, but you’d be wrong.

“I was excited,” said Sanville. “When I did my first play here in ‘92, ‘The Tropical Pickle,’ we went into previews with no second act. After previews, … Jeff (Daniels) went off somewhere and wrote, and he came in that afternoon with 18 new pages. We rehearsed it for three hours and performed it not long after. In these situations, you can panic or embrace the romance of it. That’s where the excitement is. Each time is a glorious adventure into the unknown, where no one has been before. I love that. I thrive on that.”

“The only time you’re in trouble is when the writer won’t write. We can’t rewrite a blank page. But (Crim) wrote. She wrote her brains out.”

Indeed, Crim punched out the first act of “Couples” in 36 hours (sleeping only about 6 hours), and that’s what the actors presented at CDL.

Compared to “The Third Day,” “Couples” “came so easily, because it was such a big part of my life at that moment,” said Crim, who noted that “Couples” was her most personal play to date. “Between my friends’ struggles, and thinking about the having a child myself, it was all around me. Plus, … my mom passed away when I was in high school, but I was approaching the age she had been when she had me, so I’d been thinking about that, too.”

Crim’s pregnancy has prevented her from being as hands-on as she’d like to be during “Couples”’ rehearsal process, leading up to the premiere; but Sanville and his team have filmed rehearsals for her each day and have been in constant contact. (Crim, originally from Michigan, now lives in New Jersey.)

And while Sanville is constantly reading scripts, he’s hard pressed to remember another play that focused on infertility, despite the number of people dealing with this particular brand of heartbreak.

Sanville believes that this might have something to do with the decidedly un-flashy nature of the issue. “It’s a kinder, gentler violence that these people go through,” he said.

But to Crim, the topic was a natural fit for a bittersweet comedy. “It’s got this built-in want that’s so strong,” she said. “And the conflict just creates itself.”