REPRODUCTIONOBesity Project

Pathophysiology of Obesity Regarding Fertility

• Obesity affects the endocrine system

• Endocrine changes with central obesity

• Insulin resistance results in suppression of hepatic SHBG

• Increased ovarian androgen synthesis and increased circulating free androgen

• Increased aromatization of androgens to estrogen in adipose tissue

• Leptin, a peptide secreted by adipocytes, inhibits ovarian follicular activity and steroidogenesis

Effect of Obesity on the Menstrual Cycle

• One third to half of overweight and obese women have irregular menstrual cycles

• Direct correlation between increasing BMI and cycle irregularity

• PCOS most common endocrinopathy in women

• Obesity frequently seen in PCOS patients

Effect of Obesity on Fertility

• Natural Reproduction

• Negatively affects natural reproduction through the interference of ovulation

• With weight reduction, ovulatory function and pregnancy rates frequently improve

• May reduce natural fecundity in ovulatory women- may involve potential adverse effects of insulin resistance

Effect of Obesity on Treatment of Subfertility

• Assisted Reproduction

• Higher doses and longer duration of fertility medications (gonadotropins)

• Increased frequency of cancelled IVF cycles

• Lower oocyte yields and reduced pregnancy rates

• Reduced ovulatory response to Clomiphene Citrate and higher doses required to induce ovulation

Effect of Obesity on the Male Reproductive System

• Obesity is associated with adverse effect

• Conversion of androgens to estrogens by peripheral adipose aromatization

• Relatively high estrogenic/androgenic state in obese males

• Total serum testosterone levels are reduced and gonadotropin levels are suppressed

Effect of Obesity on the Male Reproductive System

• Incidence of oligozoospermia and asthenozoospermia increase with BMI

• Scrotum remains in closer contact with surrounding tissue predisposing to higher temperatures that may adversely affect semen parameters