How does weight loss help fertility?

According to Bionews from the U.K. twenty percent of women of childbearing age are thought to be obese. It is well-established that, in women, obesity is associated with reduced rates of ovulation, increased miscarriage rates and poor response to ovarian stimulation during assisted conception. Male fertility also appears to be similarly adversely affected with evidence of a reduced ejaculate volume, reduced sperm count and increased sperm DNA damage in obese men.

These factors result in increased time to conception, and lower implantation and pregnancy rates following both spontaneous and assisted conception in those couples where either the female or male partner or both are obese. Fertility problems therefore remain a key issue for many obese and overweight individuals: in the U.K. a problem compounded by the fact that most clinical commissioning groups restrict NHS funding of IVF to those couples where the female partner has a body mass index (BMI) of 30 or less.

There is little doubt that weight loss improves both fertility and reproductive outcomes. Reductions in BMI are associated with a return of ovulatory cycles, improved sperm counts, improved conception rates for both spontaneous and assisted conception, and improvements in outcomes for mothers and their babies – not to mention the long term health benefits associated with weight loss.

But how far to go to achieve meaningful weight loss. Traditional methods such as lifestyle interventions have been shown to be largely ineffective in achieving and sustaining significant weight loss. As a result, patients and healthcare professionals alike are turning to more novel methods of weight management including weight loss surgery. Weight loss surgery for those with a BMI over 40 and those with a BMI over 35 with over associated medical conditions. Could and should ovulatory subfertility be considered an associated medical condition?

Weight loss surgery comes with its own challenges especially in a pregnancy. Concerns have been raised regarding the potential impact of nutritional restriction on the growing fetus, but this has not been a consistent finding and the vast majority of studies allayed concerns.

Of course, weight loss surgery is not without its potential risks and complications and should only be considered once conservative lifestyle measures have failed. But it would seem, for those in whom lifestyle measures fail, weight loss surgery may be a credible treatment option for those with obesity-associated subfertility. This will require a shift in thinking and an open mind from patients and clinicians alike.