Gestational Weight Gain and Gestational Diabetes Mellitus: Popular Beliefs and Emerging Evidence

The aim of this article is to review the evidence on gestational weight gain (GWG), and its relationship between abnormal foetal growth and the development of gestational diabetes mellitus (GDM). Maternal obesity is a major concern of modern obstetrics and is associated with increased maternal and foetal complications. It is becoming increasingly common and GWG has attracted an upsurge of interest. In 2009, recommendations from the Institute of Medicine in the United States revised downwards the weight gain recommendations in pregnancy for obese mothers. There is no international consensus or guidelines on GWG. There are concerns with evidence on GWG and many publications have methodological shortcomings.No causal relationship has been shown between GWG and excessive foetal growth, however emerging evidence demonstrates a relationship between birth weight and maternal fat-free mass. Interventions in pregnancy aimed at targeting GWG have not shown a decrease in excessive foetal growth and inappropriate intervention may lead to foetal malnutrition with adverse clinical consequences. While an association between pre-pregnancy maternal obesity and GDM has been shown, evidence of the relationship between weight gain during pregnancy and GDM is conflicting.A recent study has shown that fat mass gain to 28 weeks gestation does not influence the development of GDM. Careful consideration should be paid to the advice that pregnant women are given about GWG and their lifestyle before, during, and after pregnancy and we believe that it may be more appropriate to shift the focus of attention from monitoring maternal weight to increasing physical activity levels and improving nutritional intakes.