Obesity and Fertility Issues

Obesity and Fertility Issues : Obesity has long been associated with increased risk of health complications, such as hypertension, diabetes, stroke and cancer, however new research highlights the link between obesity and fertility issues.

The new study, conducted by researchers at the National Institutes of Health, and published online in Human Reproduction, found that the most obese couples (BMI of 35 or more) took 55% – 59% longer to achieve pregnancy than their non-obese counterparts.

Results and Finding

The findings were calculated by using the Fecundability Odds Ratio (FOR) to evaluate the likelihood of conception each menstrual cycle. Fecundity refers to the capacity to reproduce. Previous studies that examined the link between obesity and fertility focused mainly on the female partner, but this latest study, titled “Couples” Body Composition and “Time-to-Pregnancy”, took into account the body composition of both partners.

Longer duration to achieve pregnancy have also been noted among obese couples undergoing assisted reproductive technologies, such as In-vitro Fertilization (IVF), however participants in the latest study were from the general population, and not undergoing fertility treatments.

Five hundred and one couples took part in the study, which spanned from 2005 – 2009, as part of the Fertility and the Environment (LIFE) study, investigating a possible link between exposure to environmental toxins and fertility. Data was collected via journaling of menstrual cycles, intercourse and results from home pregnancy tests, until pregnancy was achieved, or twelve months of trying to conceive had passed.

Obesity is an increasingly widespread burden on health systems around the world, with an estimated 300 million people living with obesity. The condition is more common in developed nations, but increasingly so in developing nations too.

Defining overweight or obesity is via the use of medical Body Mass Index (BMI), which takes into account both height and weight. A Body Mass Index (BMI) of 30 or more is considered obese. More than one-third of adults in the United States are obese, and approximately 17% of children, with both males and females being equally affected.

The cause of obesity is thought to be multifactorial, and includes excess consumption of calories, over-consumption of high-sugar or high-fat foods, and lack of physical exercise.

So What Does The Data Tells Us?

Obesity may affect fertility via a number of mechanisms, although the exact pathophysiology is not yet fully understood. Obesity or overweight has been shown to affect hormones, in both men and women. Hormonal imbalance may affect women via the development of insulin resistance, which can cause abnormal menstrual cycles or anovulation, or a decrease in the quality of the eggs produced. Obesity in men can cause a decrease in testosterone levels, which affects fertility, in addition to increased rates of erectile dysfunction.

Excess weight exacerbates Polycystic Ovarian Syndrome (PCOS), which is also known to affect fertility.