Almost one in five pregnant women in the UK is clinically obese. Obesity during pregnancy puts both mother and baby at greater risk of almost every medical complication in the book. The film follows super-morbidly obese, Lucy, and husband, Barry, who have been trying for seven years to have children. After losing 20 stone, Lucy fell pregnant, only to see her weight rise again, putting her and her baby at high risk. At 21 stone, morbidly obese Jenna is pregnant with her second child. When she met her husband, David, she was a size 10, but thanks to a comfortable lifestyle and two pregnancies, her weight has rapidly risen, leading to a potentially life-threatening condition. Meanwhile, Anne and Graham try to cut down on fast food as they prepare for the birth of their son.