Minimal Weight Gain
It was only when Thomson reached the eight-month mark that she realized she gained a small amount of weight–a shocking 3 pounds in total. “I thought it was from going out all the time,” she said. I still managed to get into my clothes so I just ignored it.”
Source: http://metro.co.uk/2018/03/06/woman-who-had-flat-stomach-and-regular-periods-gives-birth-to-surprise-baby-7365647/