Althought osteoarthritis does not have the direct influence on the fertility, the pregnancy rates progressively decrease with increasing body mass index (BMI) related to obesity. The effects of obesity not only relate to chronic medical conditions but also have been strongly related to reproductive problems. Obese women have an increased risk of anovulation, menstrual disturbances, infertility, and polycystic ovarian syndrome (PCOS). PCOS is the primary cause of hyperandrogenism (high male sex hormones) and oligo-anovulation at the reproductive age and is often associated with infertility with the prevalence between 70 and 80%. Thus, if ovulation does not occur, the fertilization is avoided.
Paternal obesity negatively affects male fertility and assisted reproduction outcomes, as shown by significantly reduced fertility in the general population and reduced rates of live birth from assisted reproductive techniques (ART), as well as increased rates of nonviable pregnancy. The mechanisms that explain the relation between obesity and male infertility are not fully understood.