With the abundance of food and changes in our physical activity routine compared to previous generations, being overweight in the U.S. is becoming increasingly common. In fact, 27.5% of adult women in the US are overweight, and an additional 41.9% are obese. It is therefore not surprising that many women considering fertility preservation treatments ask themselves if their weight would prevent them from successfully freezing their eggs.
The short answer to this question is “There is no standard BMI cut-off for egg freezing.” Despite potential complications associated with being overweight or obese, freezing eggs is generally still possible, and it might be medically advantageous compared to waiting for fertility treatments until a later age. A more complete answer to the question would be: “Some limitations exist depending on the clinic.” And here is why: Obesity, which is defined as a BMI > 30, does not prevent reproductive treatments, including egg freezing. It is, however, associated with several factors that could affect the quantity and quality of the eggs retrieved, as well as the risks associated with the process.
First, obesity impairs the ovarian response to the medication used to stimulate the ovaries, which means that higher doses of the medication would be needed. It also means that the number of eggs we can retrieve from a stimulation cycle would likely be lower. In addition, obesity might be associated with lower egg quality. Certain degrees of obesity may also be associated with additional challenges such as performing ultrasound monitoring during the cycle because the resolution of the image depends on the distance of the transducer from the ovaries.
Another issue to consider is the potential elevated risk during anesthesia and the oocytes retrieval process. These challenges in the egg retrieval process are related to the lower image resolution and the greater distance the aspiration needle has to go through. As a result, there is a worldwide debate regarding weight thresholds for fertility treatments. Some countries, such as the United Kingdom and New Zealand, did set such thresholds for women who use their national insurance for their egg retrieval cycle.
The American Society for Reproductive Medicine (ASRM) did not set a BMI threshold for clinics in the United States, arguing there was no medical or ethical directive to do so.
Fertility clinics in the US, however, are free to set their own BMI thresholds, and in light of the risks described above, many of them have. In fact, nearly 65% of fertility clinics that responded to a survey stated that they did have a formal policy for obesity. Of these, 84% of centers instituted a maximum BMI threshold, often in the range of 35-45 kg/m2 (obesity starts at 30 kg/m2, and severe obesity starts at 40 kg/m2). Since most egg retrievals in the US are done at an outpatient setting where the ability to treat complications is limited, the elevated risk related to high BMIs and anesthesia is a key factor in many clinics’ decisions to set BMI thresholds.
Being overweight or obese, therefore, may have implications related to the egg freezing process, and may limit the selection of centers where the process could be performed.
It is important to note, weight is but one factor affecting the likelihood of successful egg freezing and should not be the only factor taken into consideration. Reduction of weight before egg freezing could help reduce risks and complications, and is therefore recommended. Other factors, such as age, are more significant to egg freezing success than body weight. With planned egg freezing, many women, even those with excess weight, can prolong the advantage of a younger age, and thus extend their reproductive window.
To summarize, high BMIs might be associated with several factors decreasing the likelihood of success of a person’s egg freezing journey, as well as increasing the potential risks associated with the process. Nevertheless, it is not an absolute reason to avoid egg freezing (subject to the specific clinic’s policy). It is therefore recommended that patients prioritize their health and safety when choosing to freeze their eggs, by aspiring for the best achievable weight and by finding a fertility program that can provide the best and safest care.
Dr. Ido Feferkorn is a reproductive endocrinologist at Reproductive Medicine Group in Tampa. He specializes in treating patients with infertility, PCOS, endometriosis and recurrent pregnancy loss. He also has a special interest in fertility preservation. Dr. Feferkorn’s research has been presented in international conferences such as the American Society for Reproductive Medicine (ASRM) and European Society for Human Reproduction and Embryology (ESHRE). Dr Feferkorn loves spending his free time with his wife and three kids. He chose REI because of the magic in seeing life created and accompanying the journey to parenthood.
Learn more about Reproductive Medicine Group’s egg freezing practice on Freeze.
