IVF: are we strict enough?

MAYBE it’s all in the delivery.

When Sydney IVF infertility specialist Dr Antony Lighten sees an overweight or obese patient, he doesn’t mince words – he has an “up-front conversation” about the decreased effectiveness of IVF in women with BMIs that fall outside the healthy weight range, and the increased health risks to both the baby and mother.

He insists that, so far, his frank discussion has not resulted in angry patients.

“The response has been very positive. I’ve adopted quite a strict approach…but so far I haven’t lost anybody,” he says.

“In the three years since I’ve been here, I haven’t treated anyone with a [BMI] over 35.”

It’s not that Dr Lighten simply refuses to treat these women, but that he strongly encourages them to lose weight before beginning treatment – and explains the reasons why in great detail.

Obesity often leads to lower ovulation frequency and reduced chance of conception, as well as a significant increase in the risk of complications for both the mother and the child.

On average, it takes a woman with a BMI over 35 twice as many IVF cycles to get pregnant as a woman with a “normal weight”.

IVF success rates are reduced by 25% in obese patients and 50% in very obese patients. The risk of miscarriage is also doubled in very obese patients, and the risk of recurrent miscarriage is four times higher.

But studies show that relatively modest weight loss results in a significant increase in effectiveness of fertility treatments.

About 90% of obese women who aren’t ovulating will begin ovulating normally again when they lose 5% of their body weight.

A third of overweight women will also conceive naturally if they lose 5-10% of their body weight.

“For very obese women, the chance of getting pregnant after weight loss is actually higher than through having an IVF cycle,” Dr Lighten says.

“However, it is important to note that the risks of complications for both the baby and mother will remain higher unless the woman gets down to a more normal weight.”


According to Dr Lighten, trying to get pregnant is a powerful motivator for overweight and obese women, and success rates seem to be higher in this group than in other groups he has worked with.

With that in mind, patients and their partners at Sydney IVF are jointly offered placement in a specialised 12-week weight-loss program run by an accredited dietitian, exercise coach and fertility specialist. Patients who meet their target weight loss goal but still need IVF are given a credit for the total cost of the program to go toward their fertility treatment.

Trained at Cambridge and Oxford universities, Dr Lighten worked for many years in the UK, where specialists’ attitudes on this matter tend to be more rigid than those of their Australian counterparts – and where some health authorities restrict access to IVF much more tightly than Medicare does.

Last month, the European Society of Human Reproduction and Embryology (ESHRE) published a position statement recommending that fertility doctors have “special justification” before treating severely obese women, and that they should refuse treatment for heavy drinkers who won’t or can’t minimise their alcohol consumption.

The ESHRE statement said assisted reproduction should be conditional upon lifestyle changes in cases where there was strong evidence of risk to the child, obstetric risks or lack of cost-effectiveness of the treatment – but that fertility doctors should help patients make the necessary changes. The accompanying literature review outlined the risks of smoking, heavy alcohol and caffeine consumption and overweight and obesity.

Likewise the American Society for Reproductive Medicine has also produced guidelines warning of the risks and reduced effectiveness associated with fertility treatment in these groups.

But even the task force that developed the recommendations for ESHRE acknowledges the complexity of the issue, and the need to balance “respect for patient autonomy” against the “moral weight of the interests of society and the future child”.

Here in Australia there are no cut-offs or guidelines.

Dr Lighten is concerned that specialists are reluctant to discuss the impact of weight and other sensitive behaviours with their patients “because they don’t want to offend people or… they may feel it is not their position to bar people from treatment”.

But earlier this month the president of the Fertility Society of Australia, Associate Professor Peter Illingworth, told Medical Observer that while most specialists in this country agree that the impact of weight, smoking and alcohol should be seriously discussed with patients, doctors here would be unlikely to take quite as hard line a stance as ESHRE advocates, preferring a more “compassionate” approach with less reliance on specific requirements.


IVF Australia senior fertility specialist Professor Michael Chapman holds a similar view. While he doesn’t downplay the importance or potential impact of lifestyle factors on pregnancy, he also doesn’t believe anything more formalised is necessary.

“I have a problem with the idea that there should be a set of criteria that determines whether or not to treat someone – I don’t think there should be a set of rules,” he says.

“Even if someone is overweight, they still have a good chance of success. You’re just taking them back a decade: pregnancy rates with IVF now for an overweight woman are about what they [were] for a woman with a healthy BMI in 2000.”

Professor Chapman believes comparing the Australian system to those of places like the UK or New Zealand is also unjustified.

“Medicare has determined that fertility is an important thing to be funding, whereas in the UK and New Zealand they aren’t allocating as much money, and therefore healthcare has to be rationed, and greater restrictions are the result,” he says.

“However, that principle isn’t accepted here – and I don’t think it should be.” 

Fast facts: weight and fertility

  • Rate of recurrent miscarriage is four times higher in obese women.
  • Infants of obese women have eight times the risk of neural tube defects and three times the risk of heart abnormalities.
  • Risk of gestational diabetes is doubled in overweight women, six times higher in obese women and eight times higher in morbidly obese women.
  • Stillbirth is twice as common in obese women.
  • Obese men generally have lower sperm counts, reduced spermatogenesis, increased DNA fragmentation of sperm, and increased levels of erectile dysfunction.
  • Infertility is twice as high in smokers.
  • Female smokers need more time to become pregnant, are less likely to do so spontaneously and have a higher risk of miscarriage.
  • Maternal smoking is linked to lower birth weight, a higher risk of oral facial clefts and sudden infant death syndrome (SIDS).
  • Male smokers are at risk of reduced sperm quality and concentration.
  • Alcohol consumption is linked to reduced conception, lower pregnancy rates and higher miscarriage.

Source: ESHRE Task Force on Ethics and Law

19th Mar 2010, Medical Observer