Guidelines on weight gain during pregnancy were last updated in 2009. These recommendations aimed to balance the benefits and risks associated with weight change during pregnancy. At that time, there was insufficient evidence to assess the impact of pregnancy weight gain on health conditions for women in higher classes of obesity or those who are underweight. This workshop will explore new evidence on gestational weight gain and the risk of adverse health conditions for both mother and child, focusing on women with perinatal obesity and underweight.