There’s not much fresh material in the world of the romantic comedy, but “Obvious Child” offers one new ingredient: abortion.

What it lacks is dramatic interest. There’s no zing in it.

Donna (Jenny Slate of “Parks and Recreation”) ekes out a living doing raunchy, self-deprecating stand-up at a Brooklyn bar. She loses her boyfriend due to her onstage oversharing, and shortly thereafter loses her day job. She rebounds with preppy MBA student Max (Jake Lacy, a likable Matt Damon-lite from “The Office”), bonding over a session of — I am not making this up — public urination and face-farting. Then Donna finds she’s pregnant after their one-night stand.

Donna consults her supportive roommate (warmly believable Gaby Hoffman), considers her options and chooses to terminate the pregnancy. The decision is no biggie. Director/screenwriter Gillian Robespierre may be making an empowering feminist statement: For this group of twenty-something New York free thinkers, abortion is not a grave and consequential matter.

Fine. So why make it the gimmick of the story? Fate seems to be pushing Donna toward a new, more mature path. Why not allow the most consequential decision of her life, so far, to trigger a bout of self-questioning? It could stir up some inner turmoil as counterpoint to the script’s lightweight humor. Here, the abortion decision just gives Donna a couple of silent tears and another five minutes of so-so stand-up. There was more dramatic conflict in “Mean Girls.”

The characters are smudgy, which is no great hurdle for experienced players like Richard Kind as Donna’s sweet puppeteer dad, Polly Draper as her cool, business professor mom and David Cross as a predatory fellow comic. The inexperienced Slate lacks the performing chops to earn our empathy. The film assumes we’ll like Donna because she’s cute and says crass things, which is enough for Max, who seems like he could do better.

A bigger hurdle for the film is Donna’s wishy-washy comedy routine, which we endure several times. There’s nothing groundbreaking in her point of view — I’m Young! I’m Kooky! I’m Dating! — and her gags are smilers at best.

At one point Donna’s mother gripes that she’s wasting her 780 verbal SAT telling poop jokes, and you wonder why her bits aren’t better constructed.

The bar is packed with extras who chuckle indulgently, supplying the film with its own laugh track. Lord knows, it’s needed.