OBesity Project
REPRODUCTION
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