Let's talk about the BMI and Fertility
If you are trying to conceive, navigating IVF, or working with a fertility specialist, there is a good chance the Body Mass Index (BMI) has come up. Maybe it was mentioned in passing. Maybe it was the reason a clinic turned you away. Or maybe you and the BMI have a longer history and it has left its mark on your soul.
The BMI is one of the most widely used metrics in healthcare and fertility treatment today. It is used to determine IVF eligibility, influence insurance coverage decisions, and shape how providers assess your overall health, often before you ever discuss your cycle, your hormones, your history, or anything else that actually tells the story of your fertility.
And it was never designed to do any of that.
I have had many conversations with doctors about my weight. They take one look at my BMI and tell me immediately that whatever issue I’m struggling with (plantar fasciitis, back pain, painful periods, or digestive issues) would be ‘cured’ if I ‘lost weight’ or got my BMI down 
This is a red flag 
to me – any practitioner that leads with BMI before even looking at other measures of health will not see me again.
In Ayurveda, I have a pitta-kapha constitution. Strong muscles, wide frame, dense tissue, heavy bones, and in general, a higher body mass. I have been classified as “obese” on a BMI chart for most of my adult life, despite the fact that I do not feel obese, I am fit and active, and every other marker of my health tells a different story.
I know there are many of you out there that this resonants with.
We have all been assessed based on the BMI – and it’s not based in actual science.
It is a 200-year-old administrative tool that was never designed to determine individual health, and it is often being used to decide who gets access to fertility treatment – on both sides of the index!
What is the BMI and where did it come from?
The Body Mass Index was created in the early 19th century by Lambert Adolphe Jacques Quetelet, a Belgian statistician, not a physician. His goal was to define the statistical “average man” using data collected almost entirely from white European men. Women were not included. People of color were not included. The formula was designed to measure populations and allocate government resources, not to tell any individual anything about their health.
NPR contributor Keith Devlin broke this down in his piece Top 10 Reasons Why the BMI Is Bogus (NPR, 2009), calling it “a 200-year-old hack.” There is no physiological reason to square a person’s height, which is what the formula does. Quetelet squared it because it made the data fit. The formula ignores waist size, makes no allowance for bone density or muscle mass, and cannot distinguish fat from muscle at all.
By the 20th century, insurance companies had repurposed the formula to assess risk and deny coverage, which is when it migrated into clinical settings as medical fact. In 1998, the BMI cutoff thresholds were quietly adjusted (from 27.5 to 25), and overnight, without gaining a single pound, millions of Americans were reclassified as “overweight” or “obese.”
It is quite obvious that there was no clinical trial and no longitudinal health study. The BMI was created by a statistician, with a narrow data set, and the insurance industry.
Why is the BMI considered racist and sexist?
Because the original data was collected exclusively from white European men, the BMI categories have always been applied to bodies they were never built to measure.
Research published in the Journal of the American Medical Association found that higher BMIs tend to be more optimal for Black people, and that Black women specifically do not show a significant rise in mortality risk until a BMI of 37, well above the standard “obese” threshold of 30. And yet the same cutoffs get applied across the board.
Black and brown people are consistently misclassified, told they are at higher risk than they are, or denied care based on a number never calibrated for their bodies. This is not a side effect of the BMI. It is designed right into it.
The sexism in the BMI is foundational. While Quetelet included a small number of women in some of his broader statistical work, the formula itself was built overwhelmingly on data from French and Scottish male soldiers.
Women’s bodies, which carry different hormonal profiles, different fat distribution patterns, different bone density ranges, and the entire biological capacity for pregnancy, were essentially disregarded when the medical community and insurance companies adopted it.
Since women have been left out of most medical research in general, most policy and recommendations are based on men – and let’s say it again a little louder for everyone to hear: WOMEN ARE NOT LITTLE MEN!
The BMI makes no distinction between male and female physiology at all. The same formula, the same cutoffs, applied across the board, despite the fact that a healthy amount of body fat for a woman is significantly higher than for a man, and that fat distribution in women serves direct reproductive functions. Applying a formula built on male bodies to make clinical decisions about women’s reproductive health is flawed on so many levels. It infuriates me!
Not all bodies are built the same
Western science and Ayurveda have both known this for a long time: human bodies come in distinct constitutional types, and what is healthy looks different in each of them.
Western exercise science has long used somatotypes: ectomorph (lean, light frame), mesomorph (athletic, muscular), and endomorph (larger frame, more body mass). Ayurveda knew this 1000s of years before ‘exercise science’ and called it the dosha system: vata corresponds to ectomorph, pitta to mesomorph, and kapha to endomorph.
A pitta-kapha person, like me, is a mesomorph-endomorph blend: strong, dense, built to carry more mass. That is my constitutional nature, not pathology.
The Western beauty ideal, particularly for women, has converged almost entirely on the vata/ectomorph body type: lean, light, narrow. This beauty standard is a 20th century invention, driven by Hollywood and the fashion industry, and it is profoundly out of step with both history and the rest of the world.
The earliest known representations of the female body are the Venus figurines, small statues dating back roughly 25,000 years, depicting full, rounded, pear-shaped women. They are believed to have been symbols of fertility. Ancient India celebrated voluptuous figures in sculpture and art as symbols of fertility and prosperity. Ancient Greece idealized full, plump bodies. Rome during the early Republic prized women with ample curves as signs of health and childbearing capacity. In the Renaissance, Rubens literally painted fuller bodies as the ultimate symbol of feminine fertility. In Nigeria, Ghana, South Africa, and Brazil today, fuller, rounder bodies are still associated with vitality, health, and abundance.
The FAILURE of the BMI runs in both directions!
I think it is important to point out that the BMI fails also for those who are by nature light, lean, and tiny.
The BMI “underweight” designation, anything below 18.5, carries its own set of clinical assumptions that can be equally harmful. Vata body types are naturally lean, light, and narrow. A vata person at their healthiest may fall squarely into the BMI “underweight” category without anything being wrong at all. That again is how a person was born.
Low BMI can trigger unnecessary clinical concern, pressure to gain weight before proceeding with fertility treatment, or assumptions about a person’s health that have no basis in their actual markers.
The same formula that tells a pitta-kapha person they are too heavy to deserve care can tell a vata person they are too thin to safely carry a pregnancy. Neither conclusion is grounded in the individual body in front of the provider. That is the problem.
Ojas: What Ayurveda has always know about fertility
In Ayurveda, there is a substance in us all called ojas (OH-jus). It is physically associated with reproductive fluids, hormonal health, and immunity. Charaka, in the Charaka Samhita (an Ayurveda text written over 3000 years ago), wrote: “Ojas marks the beginning of embryo.” There can be no conception, no healthy pregnancy, without sufficient ojas.
Ojas is built through nourishment, rest, and a body that is well-resourced. It is depleted by chronic stress, overwork, poor digestion, and by living in a constant state of fighting your own body.
A kapha or pitta-kapha constitution, by its very nature, has the potential to carry more ojas. The density, the substance, the groundedness that gets pathologized by a BMI chart is, in Ayurvedic terms, the very tissue that supports reproductive health.
The irony of using BMI to gate-keep fertility care, when the body type most likely to exceed its thresholds is constitutionally the most ojas-rich, again, infuriates me.
Why is the BMI used to determine fertility treatment?
Approximately 65% of IVF programs in the United States have a self-imposed BMI cutoff, typically ranging between 35 and 45, with no universal standard. The stated reasons usually involve anesthesia risk during egg retrieval and lower IVF success rates at higher body weights.
A 2024 opinion piece in NPR put it plainly: using BMI to restrict access to IVF is discriminatory. You can read it here. The piece highlights research showing weight bias among reproductive endocrinologists is as common as weight bias in the general public. These restrictions are not always about medical safety. They are often about bias, disguised as clinical protocol.
BMI cutoffs for fertility treatment disproportionately affect Black and Latina patients, who already face significant structural barriers to care. A 2024 study from Northwestern University, published in Fertility and Sterility, called directly on IVF centers to move away from BMI cutoffs in favor of individualized patient assessment.
Is the BMI an accurate measure of fertility health?
No. The BMI cannot distinguish muscle from fat, does not account for bone density, ignores waist circumference, and was never validated against reproductive outcomes. It tells you the ratio of your weight to your height and nothing else.
More meaningful markers of fertility health include hormonal panels, blood sugar and insulin levels, inflammatory markers, thyroid function, and overall metabolic health. If a provider is leading with your BMI before looking at any of those, that is worth noting.
What should I do if the BMI is blocking my fertility care?
I have had students in class who were declined treatment at their clinic or denied insurance coverage because their BMI came in just over a threshold, despite having good health markers. It is infuriating to witness, and I imagine it is devastating to live.
Here are some practical suggestions if you find yourself in a BMI battle for fertility care:
- Ask for individualized assessment. You are allowed to ask your provider to evaluate your actual health markers rather than a single number. Blood pressure, blood sugar, hormonal panels, cardiovascular markers. Those tell a more complete story.
- Know that clinic policies vary. There is no universal BMI cutoff for IVF in the US. The number that gets you denied at one clinic may be a non-issue at another. A second opinion is worth pursuing.
- Bring your data. Come with your full health picture: A1C, blood pressure history, activity level, prior records. The more complete the picture, the harder it is to be reduced to one number.
- You do not have to accept the number as the verdict. It is a policy. Policies are not the same as medicine.
Ayurveda + Fertility Yoga supports every body
Fertile Body Yoga is not a program for a certain size or BMI. It is for the body you have right now, exactly as it is.
Fertility yoga works through the nervous system, the breath, the energetic body, and the physical body. None of those pathways care what a scale says. What they respond to is consistency, intention, and showing up. I teach with every body type in mind, because I have lived in a body that the wellness world did not design its spaces for, and I know what it feels like to have to translate every cue, every shape, every instruction into something that actually works for you.
Whether you are a vata-type human who feels like she might blow away or a kapha-type human who has never once been described as petite, there is a practice here that works with your constitution and your fertility journey. Not against it.
Ayurveda is a whole system based on the understanding of individual constitution as well as imbalance. It can support you to be your healthiest most fertile self within the boundaries of your dosha – or elemental design.
Ayurveda is the health science behind yoga and the two go together like honey and a bee.
If you are ready to explore Ayurveda or yoga, I’d love to be your point person. Check out all that I offer in the Virtual Studio and see what resonates.
Resources
Devlin, Keith. “Top 10 Reasons Why the BMI Is Bogus.” NPR, July 4, 2009. https://www.npr.org/2009/07/04/106268439/top-10-reasons-why-the-bmi-is-bogus
“Opinion: Women With Obesity Are Often Restricted From IVF. That’s Discriminatory.” NPR Health Shots, January 14, 2024. https://www.npr.org/sections/health-shots/2024/01/14/1224546666/opinion-women-with-obesity-are-often-restricted-from-ivf-thats-discriminatory
Boots, Christina, et al. “Addressing Weight Bias in Reproductive Medicine: A Call to Revisit BMI Restrictions for IVF Treatment.” Fertility and Sterility, 2024. https://pubmed.ncbi.nlm.nih.gov/38750875/
“Body Size, Fertility, and Reproductive Justice.” MDPI, 2022. https://www.mdpi.com/2673-4184/2/2/11
Charaka Samhita (ancient Ayurvedic foundational text, approx. 400–200 BCE)
