Obesity is now a pandemic and
undoubtedly the greatest burden facing health services worldwide. 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: 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.
Traditionally, lifestyle interventions
have been the mainstay of pre-conceptual weight loss for those with
difficulties conceiving, comprising calorie restriction with increased
exercise, often as part of a weight management programme. However, 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 medications and weight loss surgery.
Weight loss surgery comprises
procedures that restrict stomach capacity, for examplevia compression using an
adjustable band (laparoscopic adjustable banding) or bypass part of the stomach
and absorptive parts of the small bowel (gastric bypass). These procedures have
proved effective in achieving and sustaining weight loss. Numbers of surgical
weight loss procedures performed in the UK have risen dramatically over recent
Currently, women of reproductive
age account for just under half of those undergoing weight loss surgery. At
present, NICE recommend 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?
The evidence surrounding
fertility and pregnancy outcomes following weight loss surgery is growing. It appears that the resulting weight loss can
restore the balance of reproductive hormones, restore ovulation and increase
spontaneous conception rates and that there may be an associated reduction in
miscarriage rates. Reductions in gestational weight gain have been seen in
pregnancies following gastric banding, with associated improvements in maternal
outcomes, with reductions in blood pressure problems in pregnancy including
pre-eclampsia and lower rates of diabetes in 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. What also remains unclear is how the gastric band
should be managed in pregnancy, although results are soon to be expected on a
national cohort study which should provide answers to this question.
Traditionally, women have been
advised to delay conception for a year following bariatric surgery because of
concerns over the effect dramatic weight loss may have on a developing
pregnancy, however recent data from our group and others suggests that
conception prior to one year following surgery may be safe, which may be
preferential for those who have previously struggled to conceive or are
undergoing assisted conception. Of course, bariatric surgery itself may negate the
need for assisted conception, allowing patients to achieve their goal of
conception and resulting potentially in short and long term cost savings for
the health service in terms of provision of fertility services and provision of
long term medical care for these patients.
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.