The epidemiology of obesity in reproduction

Over the last decades, overweight and obesity rates have been rising exponentially and have now reached epidemic proportions. These are significantly higher in women than men, and indeed, data from 2022 show rates varying from the lowest (12%) in the South East Asian Region to the highest (82.8%) in the Western Pacific Region. This rise is mirrored by the increasing health cost of obesity and overweight. Recent estimates put the percentage of medical spending in various countries to vary from 3 to 21%. Obesity is associated with noncommunicable diseases, such as hypertension, diabetes mellitus, and cardiovascular disorders. It is associated with 13 cancers, among which are breast, endometrial, and ovarian. The reproductive consequences of obesity are variable and include but not exclusively menstrual disorders; fertility difficulties; recurrent miscarriages; gestational diabetes, hypertension, and pre-eclampsia; postpartum hemorrhage; and fetal macrosomia. Various factors are responsible for these increasing rates (which are more marked in middle- and low-income countries). These include genetic, epigenetic, environmental, physiologic, cultural, political, and socioeconomic factors that interact in most cases, making it challenging to develop effective interventions on both a local and global scale. In this article, we review the epidemiology of obesity and the factors which modify rates, as well as an overview of the reproductive consequences of obesity. We discuss approaches to reduce the rates and that these should be at three levels: individual, national, and international.