I've met dozens of women struggling to conceive, who though healthy, exceeded a BMI threshold (usually in the neighbourhood of 35), and consequently were denied the opportunity to undergo fertility treatments and start a family.
I remember one who recounted how the fertility doctor who saw her suggested that perhaps God didn't want her to have a child (because she was unable to lose weight), but generally the reasons they're provided tend to focus on safety to them or to their future baby.
It's always struck me as arbitrary and biased as there are other conditions that confer risk that aren't exclusionary, and so I was thrilled to read a recent paper taking on the arguments in Human Reproduction Open. The paper, It is not justified to reject fertility treatment based on obesity, in my mind lays a basic groundwork for a future lawsuit.
It explains how though the risks of hypertensive disorders, gestational diabetes and caesarean sections are indeed higher in pregnancies of women with obesity, suggesting that this is a justification for withholding fertility treatment is dramatically weakened when considering that fertility treatments are not withheld from women with diabetes who in turn are at higher risks of developing hypertensive disorders, stillbirths and premature labour.
Similarly, when addressing the risks to the child - congenital malformations, premature birth with related morbidity, macrosomia and shoulder dystocia, future obesity, and a higher risk of metabolic syndrome - the authors note that children of women with diabetes also have increased risks of congenital anomalies, macrosomia and shoulder dystocia, and premature birth with related morbidity.
In speaking with an obstetrician friend, they pointed out that what's genuinely required (and unfortunately often absent or weak) is a frank discussion with the patient with obesity about the risks of the pregnancy - which indeed are real - but that denial of treatment simply on the basis of weight, is not justifiable. At worst it's conscious weight bias, at best, unconscious. Either way, it's ugly.