Birth control doesn’t come much more surreptitiously effective than this harrowing riff on Heidi Murkoff’s bestselling pregnancy guide -- the latest in Hollywood’s recent line of ghastly ensemble romcoms in which a handful of truncated, tenuously linked storylines allow for maximum star wattage and minimum screenwriting effort. (See ‘New Year’s Eve’ and ‘Valentine’s Day’ - or better yet, don’t.) Jennifer Lopez, Cameron Diaz and Elizabeth Banks are among the A-listers awaiting the pitter-patter of tiny feet in a film that aims to elicit smiles of recognition from women who have been through it all before. But unless you’ve engineered a meet-cute out of a miscarriage, or think that calling an uncoordinated toddler a ‘spaz’ is a real comedic zinger, chances are you won’t identify much with these shrill, self-absorbed parents-to-be. Lopez brings some conviction to her stock role as an infertile would-be mum; Cheryl Cole rather less to her cameo as a TV talent-show judge. Bringing a child into the world is no laughing matter, and all involved seem to have done their level best to make things as mirthless as possible.