ABSTRACT
Obesity can be defined as an excess of body fat, but the metrics to define the term vary in the literature partly because of differences in ethnic/racial groups, and the degree of obesity may relate to the morbidity and mortality created by excess body fat. Excess adipose tissue is a source of inflammatory signals that predispose to increased insulin resistance and cardiovascular risk.
This chapter reviews the male and female reproductive systems and identifies mechanisms and magnitudes of dysfunction that can be attributed to or aggravated by obesity. Obesity is associated with polycystic ovarian syndrome (PCOS) in approximately 35%–50% of the women with the syndrome but does not differ sufficiently from non-PCOS women with obesity and can be considered overlapping but separate entities. In both men and women, obesity leads to dysfunction of the hypothalamic–pituitary–gonadal axis. In women, obesity is associated with earlier puberty, dysfunctional menstrual cycles, an increased rate of infertility, and some abnormalities of pregnancy. Much of the literature on female obesity has focused on PCOS. Both obesity and PCOS have strong genetic and epigenetic predispositions. Male reproductive dysfunctions are part of the clinical manifestations of obesity. Hypogonadism, infertility, erectile dysfunction, and prostate disorders are increased in men with obesity compared to men without obesity. Weight loss in individuals with obesity of both genders by lifestyle changes, bariatric surgery, or medical therapies can improve some aspects of obesity-associated reproductive dysfunction and is recommended for multiple health reasons including improvement in reproductive dysfunction.
