This article may be too technical for most readers to understand.(January 2017) |
Obesity is defined as an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight.[1] This is often described as a body mass index (BMI) over 30. However, BMI does not account for whether the excess weight is fat or muscle, and is not a measure of body composition.[2] For most people, however, BMI is an indication used worldwide to estimate nutritional status. Obesity is usually the result of consuming more calories than the body needs and not expending that energy by doing exercise. There are genetic causes and hormonal disorders that cause people to gain significant amounts of weight but this is rare. People in the obese category are much more likely to suffer from fertility problems than people of normal healthy weight.[3]
A report carried out by the Nurses Health Study demonstrated an increased risk of anovulation in women with an increasing BMI value. Its major effects include a reduction in ovulation rate, a decline in oocyte quality, menstrual irregularities, a decreased pregnancy rate and a rise in miscarriages.[4] Obesity can have particularly damaging effects in young women as they begin menstruating earlier than non-obese girls, essentially enhancing the defects associated with obesity and fertility.[4] Obesity also affects fertility in men.[5]