Obesity & Its Impact on Fertility and IVF Success

By Dr. Surveen Ghumman Sindhu:

In the last few decades there has been a change in lifestyle and socioeconomic conditions globally. This has led to rise in obesity. Obesity has now become a major epidemic. Rising incidence of obesity is seen both in developed and developing countries. In England it is seen that 56% of women are either overweight or obese. More than 30% of women in United States are found to be obese. Prevalence of obesity is rising even in developing countries. Over the last 20 years, the obesity rates have tripled in the developing world and now it is seen that 10% of all children across the world are overweight or obese The World Health Organization has defined obesity as body mass index (BMI) more than or equal to 30 kg/m2

Increased body mass index (BMI) has effect on various aspects of infertility treatment and assisted reproductive technology (ART) procedures. The extent of this influence is however conflicting in literature. 0.1 unit increase in waist-hip ratio (WHR) leads to a 30% decrease in the probability of conception per cycle. Obesity is found to decrease successful pregnancy rates in both natural and assisted conception cycles. Ovulation and conception requires a fine complex balance of hormones released by reproductive organs. Obesity interferes with this in many ways. Overweight and obese women require a higher dose of gonadotropin, with greater number of days of stimulation and yet have lower peak estradiol levels with an increased risk of cycle cancellation due to poor follicular development. On controlled ovarian stimulation there are less number and poor quality of oocytes reported in these women They have lower fertilization and pregnancy rates. The effect of obesity upon implantation rate has also been inconsistently reported. Some studies have identified a reduction in implantation rates among the obese women. There are higher obstetric complications with a lower live birth rate in these women.

Weight loss results in regularization of the menstrual pattern, a decrease in cancellation rates, an increase in the number of embryos available for transfer, a reduction in the number of IVF cycles required to achieve pregnancy and a decrease in miscarriage rates. Obese women who lose weight tend to have spontaneous ovulation and improved response to ovarian stimulation in infertility treatment. As little as 5%–10% weight loss can improve fertility outcomes and lead to an improvement in endocrine parameters.

It is therefore advocated that for overweight and obese infertile women after initial assessment for infertility, weight management interventions like lifestyle change, diet, exercise or drug to decrease weight, should be recommended first before embarking to any treatment modality. Obesity is a modifiable risk factor. It has an effect on fertility, its treatment and obstetrics outcome. Women with increased BMI should be first encouraged to reduce weight before starting any treatment for infertility or planning conception.