Should Fertility Clinics Deny Treatment To Women With Obesity?

As blogged previously, due to concerns about poor clinical outcomes and maternal/fetal risks, many fertility clinics in Canada impose an upper body mass index (BMI) cutoff of about 35-40 kg/m2, above which they will not offer fertility treatments.  Is this the right thing to do?

The new Canadian Clinical Practice Guideline for the delivery of fertility care to women with obesity reviews the evidence on this very controversial topic.

Based on survey studies of fertility clinics, whether a BMI cutoff is used, and what BMI cutoff is used if so, is highly variable and not based on any specific or clear evidence.  Most clinics that have an upper BMI cutoff beyond which they will not offer fertility treatments cite anesthesia risk as the main reason for the cutoff.

Not only are BMI cutoffs arbitrary and without consensus, getting below the BMI cutoff goals may be very difficult for many women with obesity to achieve.  Furthermore, one study suggested that over half of the fertility clinics with a BMI cutoff did not offer any weight loss instructions or guidance to their patients - sounds to me like telling a person to row a boat but not showing them how to use the oars.

Denying fertility care to women with obesity is highly stigmatizing and discriminatory, and can worsen feelings of low self esteem, social isolation, anxiety, and depression. Denying older women fertility care until they have lost weight may cost them valuable time and any chance of pregnancy.

There is no doubt that there are risks of obesity to both the mother and the unborn child, and weight loss should be encouraged and supported.  However, as the guidelines point out, the risk of obstetrical obesity-related complications does not clearly exceed the risk of complications with other pre-existing medical conditions like hypertension, diabetes, or epilepsy. In addition, obesity related health status is a better predictor of pregnancy with fertility treatment than BMI, and also a better predictor of overall health outcomes in general, so why is there so much focus on the numbers on the scale in the first place?

As the Guideline states:

In the absence of simple, safe, and effective strategies that reliably help patients with obesity lose weight in a timely fashion, it is difficult to advocate for a universal BMI cut-off in place of careful counselling, screening for metabolic abnormalities and informed consent. 

Programs that impose BMI cut-offs should offer resources for patients to help them lose weight, and should inform patients about both the risks and benefits of delaying fertility treatment.

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www.drsue.ca © 2018

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Fertility Care For Women With Obesity

Obesity has a profound impact on reproductive health from many perspectives. We now have a brand new Canadian Clinical Practice Guideline which provides us evidence based recommendations for fertility care for women with obesity.

The Guideline, published in the Journal of Obstetrics and Gynecology of Canada, provides 21 key recommendations that answer the following questions (highlights discussed here - please see the full article for details):


What is the impact of obesity on female fertility?

Women with obesity have a risk of infertility due to a lack of ovulation that is more than twice that of women without obesity.   Even if ovulating, the physiologic ability to reproduce is still reduced.


What is the impact of obesity on MALE fertility?

While men with obesity have lower testosterone levels, it is unclear whether obesity has an impact on sperm quality and semen parameters. Men with obesity do have a higher risk of erectile dysfunction, which may be improved with weight loss.


What is the impact of female obesity on fertility treatments?

There is a lower oocyte (egg) yield with IVF. Implantation, pregnancy and live birth rates decline with increasing severity of obesity.  Live birth rates decline by 0.3-0.4% for every 1 increase in BMI over 25 kg/m2.


What is the impact of obesity on mum's health risk in pregnancy?

There is an increased risk of gestational diabetes, high blood pressure, prolonged labor, need for instrument assistance for delivery, shoulder dystocia, and C-section.   These risk increase with higher BMI.


What is the impact of obesity on baby's risk during pregnancy?

The risk of having a large baby or a baby with a congenital abnormality is increased.


What screening tests are appropriate for women with obesity seeking fertility care?

Screening should include testing for diabetes, cholesterol levels, high blood pressure, cardiovascular disease, breast cancer, and endometrial cancer.   These screenings should be done before starting fertility treatment.


What are the most effective treatments to help infertile women with obesity lose weight?

Modest weight reductions (5-10%) improve metabolic risk. Help should be offered for lifestyle modifications.  Medications to treat obesity, or bariatric surgery, should be considered for those who do not have success with lifestyle changes.

Women in their late reproductive years who have had bariatric surgery should be advised that the possible benefits of waiting for 1-2 years after surgery to conceive should be balanced against the decline in fertility related to advancing age. 

Bariatric surgery lowers the risk for large babies, gestational diabetes and hypertension, but increases risk for small babies.


Is there data demonstrating a difference in fertility outcomes for women who lose weight before pregnancy, compared to women who proceed directly to fertility treatment?

Yes - weight loss improves spontaneous fertility rates.


Should there be a national BMI cutoff for access to fertility care?

In Canada and around the world, concerns about poor clinical outcomes and maternal/fetal risks have resulted in many fertility clinic medical directors imposing an upper BMI cutoff to their program, above which they will not offer fertility treatments.  Stay tuned on this one - I am going to dedicate a whole blog post to discuss this very important and hotly debated topic.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2018

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