Fig. 2. Body mass index is a poor discriminator of obesity-related adverse pregnancy outcome.

Approximately 20% of all pregnancies are in mothers who are obese at the time of antenatal booking (around 11 weeks’ gestation) and undergo expensive, intensive antenatal monitoring. However, this percentage varies widely across different countries. Approximately one-third of obese mothers have an adverse pregnancy outcome. Obese mothers appear to be twice as likely to suffer an adverse pregnancy outcome than non-obese mothers, yet there is little information on how this varies between populations. There are a variety of obesity-related adverse outcomes of varying prevalence (represented by circle size). The underlying cause of adverse outcomes in obese mothers is often linked to metabolic dysregulation.