Those Other Women (Be careful whose side you take) - Nicola Moriarty

It was supposed to be harmless fun. Poppy created a Facebook group to vent just a little about smug mummies at work. After all, her best friend betrayed her in order to have a child - with Poppy's husband. She just never expected the group to take off the way it did. Or that the 'other women' are in turn heartily sick of being judged by non-mums and stay-at-home mums alike. And soon the rivalry spills into the real world.