Do You Weigh Too Much To Undergo Fertility Treatments?

A recent article by Medi Weightloss Clinics is asking the question, should an increased body mass index (BMI) be enough to prevent women from undergoing fertility treatments? While the question is controversial, several countries have adopted this policy. For example, in New Zealand, women with a BMI > 32 kg/m2 are banned from fertility therapy, and women with a BMI > 32 kg/m2 are not allowed to have an egg retrieval under sedation in British Columbia.

It is well-known that obesity is associated with infertility, primarily due to hormonal causes and Polycystic Ovarian Syndrome (PCOS). Brewer et al (2010) reported that there is a link between abdominal obesity and decreased pregnancy rates. In addition, important components of assisted reproduction, such as ultrasound imaging and egg retrieval are hindered by obesity, as is super-ovulation, thus decreasing overall pregnancy rates. Shah et al (2011) compared obese women with a BMI > 40 kg/m2 and normal weight women and found that birth rates were 50% lower in the obese group. It is also known that obesity leads to pregnancy complications such as, hypertension, gestational diabetes, prolonged labor, increased blood loss, unexplained stillbirth, and increased neonatal admissions.

Despite the clear evidence, there is on ongoing debate over whether there is enough conclusive evidence to withhold fertility treatment. Balen (2006) reported that a BMI as high as 35 kg/m2 did not affect the overall outcome of ovulation induction in women with PCOS. Dokras (2006) reported that success of in vitro fertilization (IVF) outcomes were not affected by obesity up to a BMI of 40 kg/m2 although the cycle cancellation in the obese group was 25% compared to 11% in the normal BMI group. Maheshwari et al (2009) reported that there were no differences between normal weight and obese women in terms of associated costs: the cost per IVF cycle, cost of prenatal care, cost per positive pregnancy test, or cost per ongoing pregnancy. However, the researchers did conclude that women should lose weight due to the increased obstetric complications associated with obesity.

On the whole, it is important to educate overweight women who are infertile on the benefits of weight loss. Obese women dealing with infertility should be counseled that a high BMI may negatively affect their ability to conceive and is associated with pregnancy related complications.

Balen, A.H. et al. (2006). British Journal of Gynecology, 113, 1195-1202. Brewer, C.J. et al. (2010). Reproduction, 140, 347-364. Dokras, A. et al. (2006). Obstetrics & Gynecology, 108, 61-69. Maheshwari, A. et al. (2009). Human Reproduction, 24, 633-639. Shah, D.K. et al. (2011). Obstetrics & Gynecology, 118, 63-70.