Prioritising for fertility treatments—should a high BMI exclude treatment?



This article is corrected by:

  1. Errata: Erratum Volume 114, Issue 1, 124, Article first published online: 6 December 2006

Dr CM Farquhar, Fertility Plus, Auckland District Health Board and Department of Obstetrics and Gynaecology, University of Auckland, Auckland 1020, New Zealand. Email

Resources for funding of health services are limited and therefore decisions about who can have treatment need to be made. Until recently, decisions to commence fertility treatments were made by clinicians without the need to seek approval for funding. However, it is no longer possible to decide that a particular treatment option seems like a ‘good idea’ without considering its effectiveness and safety as well as the resource implications of providing that treatment. In many health systems, decisions about access to care have devolved into joint responsibilities between clinicians, policy makers and those who fund health care. With governments directing the available funding, the clinician’s role has been to prioritise and rank patient need, while that of management has been to calculate how many patients can be treated.

The report by Gillett et al.1 describes the unique system that was introduced in New Zealand in the mid-1990s for ranking patients for elective, publicly funded procedures by the development of clinical priority access criteria (CPAC) for several procedures. A CPAC for patients with infertility seeking assisted reproduction techniques was introduced in NewZealand in 2000.2 Prior to this time, access to publicly funded assisted reproduction technique was unequally distributed, and the CPAC model was designed to give preference to couples with infertility who were least likely to conceive without treatment. The majority of public funds were to be used for in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) that are expensive treatments with low success rates compared with many medical and surgical interventions in other areas of health care. The cost of an IVF cycle in New Zealand is approximately $6000 and the cost of an ICSI cycle is approximately $8000. Following a completed IVF procedure where all embryos are used, between 25 and 50% of couples will ‘take home a baby’. With these costs and outcomes in mind, the New Zealand Ministry of Health restricted access to publicly funded IVF and ICSI by using the CPAC approach. However, if a woman had a body mass index (BMI) of >32 kg/m2 then, regardless of the CPAC score, she was required to lose weight first.

The effect of obesity on reproduction

Women who are overweight are more likely to be infertile and have a lowered success rate with IVF and ICSI compared with women of normal weight. A study of 1880 women with infertility and 4023 control women showed that anovulatory infertility was three times more common in those with a BMI of >27 kg/m2.3 Furthermore, being overweight also adversely affects the reproductive outcome of ovulation induction. In a cohort of 270 women, with polycystic ovary syndrome (PCOS) who received either clomiphene citrate or gonadotrophins for ovulation induction, almost 80% with a BMI of 18–24 kg/m2 ovulated at 6 months compared with only 12% of women with a BMI ≥ 35 kg/m2.4 Overweight women also require higher doses of clomiphene and gonadotrophins.5 There is also evidence that women who are extremely overweight have a higher chance of failure to conceive with assisted reproduction technique cycles.6,7 Several studies have reported that very obese women have half the chance of conceiving with assisted reproduction technique compared with women with a normal BMI range.8–10 Only one study has suggested that obesity was not important in the outcome of IVF.11

Once pregnant, then it is well recognised that maternal obesity is associated with an increased risk of both maternal and neonatal complications.12,13 Obesity is associated with an increased risk of hypertension, gestational diabetes and thromboembolic disorders as well an increased caesarean section rate.12–15 Macrosomia, admission to neonatal intensive care, birth defects, stillbirth and perinatal death are all increased in the infants of women who are obese.3,14 Pregnancy in obese women is more costly because of increased caesarean section rates, length of stay and admission to neonatal services.15 In women with PCOS and a BMI ≥ 35 kg/m2, 20% of pregnancies ended with stillbirth and another 20% had congenital anomalies.3 The supposed mechanism that increases the stillbirth and congenital anomaly rate includes insulin resistance and incipient or undiagnosed diabetes. Similar trends have been shown in an Australian population of women giving birth, with a doubling of birth defects from 1.9% in women with a BMI of 30–40 kg/m2 to 4% in women with a BMI of >40 kg/m2.13

Weight loss has been shown to improve fertility both by improving spontaneous ovulation and also by improving the chances of success with assisted reproductive technology. Surprisingly, modest weight losses of only 10% over only 1–2 months has been shown to be effective in improving hormonal profiles, menstrual regularity, ovulation and pregnancy rates.16,17 The mechanism for this effect is probably the improved insulin sensitivity. As a result, weight reduction for overweight women has been strongly recommended.5

The New Zealand CPAC for assisted reproduction

The introduction of the CPAC model has allowed greater and fairer access to assisted reproduction technique in New Zealand. Prior to the introduction of the model, access across the country was highly variable, some couples could access up to three cycles of IVF whereas others did not have any. Introduction of the CPAC enabled all eligible couples to access one IVF treatment, and later in 2004, this was increased to two cycles. A critical feature of the model was that an individual woman’s BMI was used to access the CPAC itself. For women outside the BMI range of 18–32 kg/m2, acceptance for CPAC scoring was only on the basis that they had undergone weight improvement programmes and had demonstrated weight loss or gain.

In this month’s journal, we have highlighted the challenges of providing fertility treatment to women who are severely overweight. As providers of fertility services, there is a responsibility to consider the risks of the treatment to the woman and also the offspring. We have reported on the development and implementation of a policy that at first read may seem unfair and rigid as women with a BMI greater than 32 kg/m2 are less able to access fertility treatments. The policy has been in place now for 5 years and our experience has shown that women in the BMI range 32–35 kg/m2 are not too disadvantaged by the system. These women were able to start assisted reproduction technique by initiating lifestyle changes that enabled weight loss. To remove the BMI ‘threshold barrier’ would have meant others missing out in a system that has limited resources. We believe the restriction of access has improved standards of care.

In spite of the acknowledged limitations of the report, we believe that the New Zealand CPAC system has merit, as it has attempted to introduce transparency and equity into the system and at the same time to encourage the adoption of a healthy lifestyle by insisting on weight loss and stopping cigarette smoking. By encouraging lifestyle changes such as weight loss, the message that obesity is a major health problem is reinforced. In addition, by reducing weight prior to pregnancy, obstetric complications and health problems for the offspring should also be improved as well as reducing the costs of the assisted reproduction technique treatment. Lifestyle changes such as weight reduction and exercise are firmly in the control of patient. This is an important public health message for women and their families in the reproductive years, and our experience shows that some women will achieve these. Fertility services have an opportunity to promote this message. Insisting on a cutoff for BMI in order to access fertility treatments and investing instead in weight reduction programmes prior to undertaking assisted reproduction technique in overweight women makes sense and is surely good medicine.