4 Ways The Use of BMI Damages the Reproductive Health of People in Larger Bodies

4 Ways The Use of BMI Damages the Reproductive Health of People in Larger Bodies

The Body Mass Index (BMI) might not be a familiar concept to everyone, but it continues to influence the way medical professionals assess their patients’ health, and the type of care we receive as a result.


BMI is a formula that was created by Lambert Adolphe Jacques Quetelet almost 200 years ago. The equation is based on an assessment of height and weight.  


Quetelet was not a physician, he was a mathematician, and BMI was never intended to calculate a person’s overall health. However, it is still used in medical settings in this manner to this day.


Within the BMI framework, folks are classified as “underweight”, “normal weight”, “overweight” or “ob*se”, and are typically treated according to this body type. (Note: While ob*sity is a scientifically accepted term, it has been weaponized and used to pathologize and dismiss fat people’s bodies, and therefore is considered a slur in many communities.)


BMI is unreliable because it doesn’t take into consideration muscle and fat distribution. On top of that, its origins are problematic. In an article for Good Housekeeping, Adele Jackson-Gibson discusses its racist history, including the fact that the data collected to create this formula was primarily based on the bodies of white European men.


Additionally, BMI provides zero context on how things like institutionalized racism and chronic stress can impact one's mental and physical health. Using it as a benchmark for wellness is not only damaging, but also dangerous.


And when it comes to reproductive health, the impacts of BMI are just as harmful.


Here are some ways this can play out:


Gatekeeping Pregnancy


In a New York Times article about pregnancy and weight, journalist Virginia Sole-Smith delves into the stories of fat people who have tried to become pregnant, and the doctors who recommend weight loss as a first plan of action. As Sole-Smith discusses in her article, the idea that larger bodies are more infertile can be traced back to a study in The New England Journal of Medicine from 1952, in which two Boston physicians determined that those at an “ideal weight” had less menstrual disturbances than those at a higher weight.


Because of these studies, and the dominant albeit inaccurate belief that thinner means healthier, doctors often suggest weight loss to larger people trying to become pregnant.


But this advice is incredibly flawed, because over 95% of weight loss attempts “fail”, and people end up gaining the weight back. This is called “weight cycling”, and it is more dangerous than staying at a heavier weight.


Encouraging women to make their bodies smaller while looking to conceive or while pregnant can lead to a less physically and mentally healthy mom, and therefore, a less healthy baby. This is especially the case if the mother has a history of disordered eating.


Denying Access to Fertility Treatments


In an article for HuffPost UK, journalist Rachel Moss writes about England’s healthcare system (the NHS) and its use of BMI as a barrier to fertility treatment in larger people. As we know, BMI is not a useful tool in judging someone’s health, nor is it an accurate way to determine whether people will have successful pregnancies. But folks with high BMIs are continuously denied IVF treatment, not only in England, but in Canada and across the world.


Many studies go against this methodology. In fact, research from Penn State College of Medicine in Hershey shows that there is “not strong evidence to recommend weight loss prior to conception in women who are ob*se with unexplained infertility.”


Still, doctors are more likely to discriminate against their overweight and ob*se patients, often because of the belief that they are unhealthy due to their inaction regarding diet and exercise. These prevailing attitudes create real obstacles for fat people trying to start a family.


Contraception Matters


BMI also impacts larger peoples’ attempts to avoid pregnancy. Plan B is considered safe to take at any weight, but it may be less effective for those above 155 pounds. Additionally, oral contraceptives may have increased failure rates in women above certain BMIs. A higher dose is often recommended to mitigate these factors.


The problem is, the research around this is conflicting and minimal, so it’s hard to say how much of an impact this truly has. Therein lies the problem—this uncertainty shows how fat people are often not even considered in conversations around family planning and sexual discourse.


Weight Bias


Weight discrimination towards fat patients by those in the medical profession is a highly important but often overlooked factor when it comes to reproductive health. If you’re constantly told to change your body (even when you’ve tried almost everything), this has a real impact. If you are made to feel responsible for any and all health problems, whether they pertain to reproduction or not, those negative emotions associated with doctor’s visits are going to take their toll. This results in fat people avoiding doctor’s offices to the detriment of their own health.


Even when patients continue to see their doctors, the stress associated with these visits has a real effect on mental health, which in turn can lead to physical symptoms. These physical symptoms are often blamed on weight rather than weight bias. It becomes a vicious cycle.


When you’re pregnant and fat, this type of stress and shame can become dangerous for mom and baby.


Medical professionals need to be educated on the latest research regarding health and ob°sity. BMI, and weight in general, is not an effective tool for measuring a nuanced and compassionate view of health. Being fat, even if you are “unhealthy”, is not a reason for inadequate medical care, and weight loss is a highly complex, personal thing that should be discussed in a careful, considerate way.


Larger people deserve the same care as everyone—to be kept in the conversation, to be treated with compassion, and to feel respected and heard when it comes to their reproductive healthcare.

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