Overweight and obesity are terms describing the accumulation of abnormal or excessive amounts of body fat which is associated with comorbidities such as venous thromboembolism, type 2 diabetes, cardiovascular disease and cancer.1
Obesity is associated with menstrual disturbances and oligo-ovulation, and obese women’s fertility can be reduced.2 They are at risk of developing complications during pregnancy such as gestational diabetes, hypertensive disorders, pre-eclampsia and foetal macrosomia (high birthweight).3 Risks to the foetus include neural tube defects, orofacial defects and cardiac abnormalities.
Body mass index (BMI) is used to determine obesity. It is calculated by dividing weight by height. A BMI of ≥25 to 29 is considered overweight and one of ≥30 as obese. In 2014, over 13% of the world’s population were classified as obese, while in the UK 28% of all adults and 29.2% of women were classed as obese. These proportions had increased from 25.5% and 26.8% respectively between 2010 and 2014.4