There are a significant number of overweight and obese females who suffer infertility. This could be a consequence of irregular periods and frequently anovular (non-ovulatory) menstrual cycles. A large percentage of those infertile patients have Polycystic Ovarian Syndrome (PCOS), a disorder often associated with obesity, chronic anovulation, and menstrual irregularity.

Anovulation is also seen in patients with a body mass index (BMI) of less than 30 due to hormonal imbalances. Although the exact mechanisms of how obesity affects fertility are not well understood, there is an apparent insulin-mediated hyperstimulation of ovarian steroid production and decreased sex hormone-binding globulin.

Obesity impacts IVF treatments, and has been associated with the following:

• Early pregnancy loss after IVF
• Decreased pregnancy rate
• Decreased fertilization
• Higher gonadotropin requirements
• An impaired response to gonadotropins.

The cause of a poor IVF treatment outcome may be due to poor oocyte quality with subsequent lower fertilization and/or implantation defects caused by a qualitatively poor endometrial milieu. Finally, there are a number of endocrine changes that are associated with being overweight or obese.