In July 2009, Allen began dating Sam Cooper, a builder and decorator. On 5 August 2010, Allen announced that she was pregnant with her and Cooper's first child, later confirmed to be a boy, due early in 2011. She experienced complications early in the pregnancy, including "about a week and a half of really heavy bleeding." In late October, six months into her pregnancy, Allen contracted a viral infection which caused her to suffer a stillbirth, announced on 1 November. On 6 November, Allen was admitted to a hospital, where she responded well to treatment for septicaemia. In February 2017, Allen explained that she was diagnosed with post traumatic stress disorder after the stillbirth.