The "Magic Number Study" & How Patients Can Use It

The latest study of assisted reproductive technology to make big news is one conducted by a team of European university- and hospital-based researchers and published in the journal, Human Reproduction. In "Association between the number of eggs and live birth in IVF treatment: an analysis of 400 135 treatment cycles", researchers conclude that women who had 15 eggs retrieved during one IVF cycle were more likely to have a live birth than those with fewer or more eggs.

In a medical arena ripe with desperate-feeling patients and a primary treatment (IVF) that is effective but dependent on many variables (including some that are still a mystery to scientists and clinicians alike), most research that zeros in on a single point of success makes big news. One of its main appeals to fertility consumers: the simplification of a very complex process.

If only IVF success were as simple as making sure your patient produces the right number of eggs. Any fertility specialist knows how much more is involved in helping facilitate a conception and live birth. Patients, too, are often savvy in their knowledge of statistics and how those numbers apply to not just "real life" but to their particular infertility situation. There will always be some, however, who read the attention-grabbing headlines and fall into a trap of hope based on misunderstanding.

Importantly, the researchers are making sure media reports include an important piece of data from their study: The magic number doesn't do much for women over 40 who are using IVF.

From a Globe and Mail article on the study:

"While 15 eggs may be the perfect number, it doesn’t offset the effects of aging. In the British study, the predicted live birth rate with 15 eggs retrieved was 40 per cent for women aged 18 to 34, compared with 16 per cent for those aged 40 and over."

Dr. Sonja Kristiansen, Medical Director of Houston Fertility Center, offers a compassionate yet clarifying response to her patients who bring "exciting news" into consultations.

"Hope -- for your treatment and, more importantly, about the new life you're working hard to create -- is indeed a factor in your stress level. So I understand patients grabbing for hopeful data, but I caution them to not put all of their hope in one aspect of the IVF process."

Dr. Kristiansen adds that it's also helpful for clinicians to have a number at which to aim, but that on a per-patient basis, it's not that meaningful.

She wrote in her related Question & Answer blog, "So while it's handy to have a nice, neat number to aim at, chances are good you won't find me or my colleagues calling off your stimulated cycle because there are only 5 or 10 eggs in there -- not for that reason alone. If there are other factors at play in a cycle -- for some other reason your health is at risk -- cancelling a cycle may be the best thing to do. But never just because your ovaries didn't hit the magic number!"

Dr. Kristiansen adds that patients can add this bit of research news to their own knowledge for an idea of how tenuous conception can be, even when all the right things are being done. "Use that information to motivate yourself when necessary, to do what you can about the fertility factors you can control, like your lifestyle choices -- nutrition, weight, stress, medications, etc." But don't, she says, think all hope is gone if your ovaries don't make 15 eggs.



Study abstract:
Association between the number of eggs and live birth in IVF treatment: an analysis of 400 135 treatment cycles

Hum. Reprod. (2011)
doi: 10.1093/humrep/der106
First published online: May 10, 2011