Rose Byrne plays a beleaguered mom in Mary Bronstein’s If I Had Legs I’d Kick You (C-), but its protracted, insistent vibe of showing the horrors of motherhood will likely prove an endurance test for audiences in the process. Bronstein makes some big swings such as never actually showing the main character’s daughter, instead representing her as a shrieking off-screen nuisance. Then there are the all-too-obvious allegories like a gaping hole in the ceiling of their residence, where endless water flows forth. Byrne is committed to her role and acting her heart out of all the maternal madness in the threadbare plot. It’s a lot of heavy acting and heavy-handedness adding up to not much. The film erodes its own summons to empathy with each passing frame, and even Conan O’Brien playing a counselor can’t cushion the film’s blunt force. In some ways it’s the Reefer Madness of movies about deciding to have a kid, and yet it’s unclear if that’s even the point it’s trying to make.