Micro-video: The Skinny on Obesity: Logistics and Special Considerations for IVF in the Obese Patient

Presenter: Eve C. Feinberg, M.D., Northwestern University Feinberg School of Medicine


This talk focuses on special considerations for IVF in the obese patient
There has been a marked increase in obesity in women of childbearing age. In 2015, only 33% of women were classified as being in a healthy weight group with 33% classified as obese and another 38% of women overweight . By 2035 the healthy weight group will decrease to 28%, while 33% will be overweight and 39% obese. Women of healthy weight are the minority and overweight and obese is the majority.

There is a well-established link between obesity and infertility such that women who have an elevated BMI have:
  • Longer time to conception
  • increased rate of miscarriage
  • ovulatory dysfunction
  • menstrual irregularity
In some cases, morbid obesity can be so physically restricting that couples are unable to have successful intercourse and thus unable to achieve pregnancy.

This past June an article was published in the NY Times that discusses the controversy regarding BMI restrictions and IVF. This was a polarizing piece and touched upon the medical and psychosocial impact of obesity and IVF.

Obesity impacts IVF in several ways. First, as a woman’s BMI increases, gonadotropin requirements increase.

IVF monitoring with ultrasound may not be as accurate in obese women as visualization is more challenging.

As most retrievals are done in an outpatient setting, anesthesia concerns must be taken into consideration. Many clinics employ mobile anesthesia units and are not fully equipped to handle major complications that could arise when trying to sedate an obese patient.

The egg retrieval itself can be more challenging in an obese woman. Sometimes a transvaginal retrieval is not possible due to position of the ovaries or other anatomic factors and an abdominal retrieval is necessary.

And finally, embryo transfers are done under the guidance of transabdominal ultrasound, making them more challenging in the overweight and obese population.

Most will argue that the reason for BMI cutoffs is an increased anesthesia risk for the obese woman.

In a study out of Brigham and Woman’s Hospital they assessed the effect of class III (BMI 40-49.9) and class IV (>/=50) on oocyte retrieval complications and outcomes.

All patients, regardless of BMI, were evaluated before the day of the procedure by an anesthesiologist by phone or in person. Patients with a complex medical history or comorbidities had this assessment completed in person. In addition, before treatment, all patients with BMI ≥ 40 kg/m2were required to have an in-person anesthesia consultation for airway assessment and preoperative planning, a maternal–fetal medicine consultation, and nutrition/weight loss management counseling was strongly advised. Patients with a BMI ≥ 60 kg/m2 were not candidates for IVF treatment, on the basis of a multidisciplinary consensus group guideline created in conjunction with the anesthesia and maternal–fetal medicine divisions.

There was an increased dose of propofol and fentanyl needed in the obese groups 98.9% were performed under total IV anesthesia.

CPAP for oxygen desaturation was required in 17.6% patients with a BMI >/= 40 kg/m2, compared with 2.7% in patients with a BMI < 40 kg/m2.

14.1% of patients with patients with a BMI > 40 kg/m2 required supplemental oxygen postoperatively for oxygen desaturation compared to 8% patients with a BMI < 40 kg/m2.

A transabdominal approach for oocyte retrieval was required in 7.0% of patients with a BMI>/= 40 kg/m2 and 0.9% in patients with a BMI < 40 kg/m2.

The authors concluded that serious intraop and post op complications were uncommon across all BMI groups. However, minor complications were more common in class III and class IV obesity.

Around the world fertility treatment is withheld from women above a certain BMI, with a threshold ranging from 25 to 40 kg/m2. Resource allocation towards fertility treatment has been extensively debated in countries where fertility treatment is publicly-funded. Medical, social and ethical aspects have been evaluated prior to allocation of resources. Analysis of cost-effectiveness, risks and benefits and poor success rates have led to calls of restricting fertility treatment to obese women.

Arguments FOR a BMI cutoff cite:
  • Lower success rates of fertility treatment in overweight and obese women
  • Increased Obstetric and Perinatal Complications
  • Increased cost of fertility treatments
As for success, a retrospective cohort study of 239,127 fresh autologous IVF cycles was performed with the use of data from the SART CORS database from 2008 to 2010. Cycles in patients with a normal BMI (18.5–24.9 kg/m2) were used as the reference group.

Among the sample size of 239,127 cycles, more than one-half of the patients fell into the normal BMI reference range.

  • The mean number of oocytes retrieved was inversely proportional to BMI
  • The percentage of cycle cancellations increased with increasing BMI
  • Implantation rate decreased with increasing BMI
  • Clinical pregnancy rates were highest in the normal and underweight BMI categories
  • Pregnancy loss rate significantly increased with increasing BMI categories
  • Live birth rate also decreased with increasing BMI, from a high of 31% in low- and normal-BMI cycles to a low of 21% in cycles with the highest BMI (>50 kg/m2)
This study showed worsening of all primary outcomes in groups with higher BMIs.

A direct contributor of success with IVF is selecting the correct embryo to transfer. There has been some debate as to whether aneuploidy rates are higher in obese women. In a study from NYU in 2015, the authors retrospectively analyzed 279 women ages 20-49 who were doing PGT and who had BMI calculated on the day of oocyte retrieval.

Multivariate logistic regression failed to show a statistically significant relationship between BMI and euploidy in underweight, overweight and obese patients compared with the normal-weight reference group.

The authors concluded that the negative impact of being overweight or obese on IVF and reproductive outcomes may be related to factors other than embryonic aneuploidy.

There are many principles of bioethics in healthcare decision making.

This leads us to ask the questions of whether patients have the right to refuse weight loss and to still access IVF treatments?

It also leads us to ask the question of whether doctors should have to treat patients who are at high risk for adverse obstetrical and perinatal outcomes?

The ethical principles at play here are autonomy, nonmaleficence and proportionality.

Autonomy: allowing or enabling patients to make their own decisions about which health care interventions they will or will not receive.

Nonmaleficence: principal of not inflicting harm on others.

Proportionality: weighing and balancing individual freedom against wider social goods.

In summary: one must weigh the risks and benefits in deciding whether to restrict access to IVF for those with elevated BMIs.

The arguments AGAINST weight restriction favor patient autonomy as the guiding principal. IVF risk is perceived, weight loss is hard, often not successful and the impact of age is significant.

The arguments FOR restriction favor nonmaleficience, it can be argued it is unethical to subject a patient to lower IVF success rates and increased obstetric and perinatal complications.

One can conclude that it is ethically justifiable to have BMI restrictions for access to IVF treatments, but one should question whether these cutoffs should just be for IVF or should they encompass all treatments that lead to pregnancy? As for the exact BMI above which to restrict, the debate continues…

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