Can you be too fat to receive fertility treatments?

Ignorance and profit motif deprive obese women of access to fertility treatments

Learning that a considerable number of fertility clinics “refuse to treat prospective mothers they consider too large,” Virginia Sole-Smith asked exactly the question in the headline of this piece in a June 18, 2019 article in The New York Times Magazine. She addressed many of the social and ethical aspects well, though without giving much attention to the biological effects of obesity on mostly female fertility.

When you are told you are too fat to get pregnant, New York Times Magazine

Presenting a 32-year-old woman who at that point weighed 317 pounds and had been trying to conceive for three years as an example, she quoted that patient in a very telling sentence: “When you’re fat, you get used to people assuming weight loss will fix everything wrong in your life” and that, often, also includes infertility.

Obesity is associated with lower fertility, but the question is why

And there is, of course, some truth to the fact that obesity reduces spontaneous pregnancy chances and also adversely affects pregnancy chances with fertility treatments, including in vitro fertilization (IVF). The literature to support the association between obesity and lower fertility is very convincing, but as so many times in medicine, things are a little more complex than they appear on the surface: Like with almost any diagnosis (and obesity is a medical diagnosis), one obese patients is not necessarily like the next. Causes of obesity can vary greatly and, with it, why the obesity in a given case is associated with infertility.

Let us assume as examples, two very different scenarios: In one, husband and wife are both morbidly obese (that morbid obesity affects both partners, is not an uncommon finding). In such a case, their infertility may be, simply, mechanical, in that intercourse has become physically difficult. As an alternative scenario, let us assume a couple, where the female suffers from the classical phenotype of the polycystic ovary syndrome (PCOS), often associated with severe obesity and her husband is perfectly slim. In the latter case, the couple’s infertility may have nothing to do with the female’s obesity but may be caused by her being anovulatory (not ovulating an egg every month), a classical symptom of PCOS.

Specific cause of obesity-related infertility determine the proper treatment

Not only are causes of infertility different between both couples, but treatments also must be appropriately adjusted. In the first couple, just making it possible for semen to reach the woman’s egg may be enough to help her conceive. In other words, simple intrauterine inseminations (IUIs) may be sufficient to overcome the couple’s infertility. In the second case, however, such a treatment may make no difference if the woman’s ovaries do not release an egg every month. Being anovulatory in association with obesity has also a simple solution in many patients: just losing a relatively small amount of weight (often no-more that ca. 15 pounds) may convert this anovulatory PCOS patient back into a regularly ovulating woman. Under such circumstances, and especially if the woman is still young and there is time for a serious attempt at weight loss, a weight-loss strategy may be warranted. In the first couple, this, however, likely would not be successful because both of them only unlikely will lose enough weight to address their mechanical infertility.

In other words, just like when discussing various other causes of infertility, individualization of medical treatments in association with female obesity is as relevant as with any other medical diagnoses. This is a point we have made in the pages of the VOICE on numerous occasions before. For fertility centers to flatly refuse treatments to patients who are obese, therefore, makes little sense and one, therefore, must ask why this practice, as pointed out in the New York Times Magazine piece, is so common.

IVF centers refuse treatment to obese women to maintain high pregnancy rates

This question has two potential answers: The first is, simply, ignorance. As the above-quoted patient pointed out, for many physicians–not only those in infertility practice–weight loss is the first, second and even third automatically recommended treatment, independent of what the underlying causes of obesity may be.

In infertility practice, there is also a second likely motivation at play, which, unfortunately, increasingly dominates how infertility, and especially IVF, is practiced: the economics of modern-day IVF. Why economics matter is again the consequence of two distinct motivations: First, IVF centers in many markets, still, compete based on IVF cycle outcomes. The higher the pregnancy/live birth rates are, the more attractive they will appear to the public, largely unaware of the fact that any IVF center can dramatically improve outcomes by, simply, not treating poorer prognosis patients. And, as noted above, obese patients, indeed, face lower pregnancy chances than lean women.

Obesity can negatively affect egg quality

Though all biological reasons for the lower pregnancy rates in obese women are still not well understood, interesting recent work has shed light on at least some of the pathophysiology of how obesity affects female fertility. This new knowledge offers considerable new therapeutic challenges in patients. What recent studies demonstrated with surprising clarity is that eggs (oocytes) in obese patients intracellularly accumulate excessive lipid loads, which, with considerable likelihood, reduce egg quality and, with it, pregnancy chances of embryos produced with such eggs.

With significant weight loss, these lipids in oocytes decline in concentration, but the weight loss must be much more extensive than the loss required to reinitiate ovulation in obese PCOS patients. Consequently, such weight loss is much more difficult to achieve and, realistically, only rarely an option for morbidly obese patients. The one exception may be those women who are willing to undergo weight loss surgery, which can bring about relatively quick weight loss of adequate size.

Because of significantly lower pregnancy chances, obese patients, therefore, are automatically considered poorer prognosis patients and, therefore, undesirable for an IVF program’s outcome statistics. Since the underlying cause is egg-related, it, therefore, makes sense to many programs to recommend egg donation to such patients, which, of course, offers better pregnancy and live birth chances. Profit margins in egg donation cycles are, in addition, for most IVF clinics better with third party donor egg cycles than autologous cycles, thereby reinforcing economic incentives for IVF centers to refuse treatments with “own” eggs and advocate the use of donor eggs.

These circumstances, therefore, very much mimic the dynamics for older women, previously discussed in these pages. At most IVF centers, older women are refused fertility treatments with use of own eggs and, after ages 42-43, pretty automatically referred into egg donation. CHR’s comments are not meant to argue universally against use of donor eggs in obese women but here expressed opinions, like in older women, just make the point that egg donation should not be considered a first resort, but the last. Moreover, in obese patients just as in older patients, egg donation also must be understood by patients as their own choice, and not their physician’s.

This is a part of the July 2019 issue of the CHR VOICE.

Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.