The magic number – 15
17 Jun 2011 by Evoluted New Media
Doctors should aim to retrieve 15 eggs from a woman’s ovaries in a single cycle in order to have the best chance of a live birth after assisted reproduction technology say researchers.
Doctors should aim to retrieve 15 eggs from a woman’s ovaries in a single cycle in order to have the best chance of a live birth after assisted reproduction technology say researchers.
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Scientist discover the optimum number of eggs to retrieve during fertility treatment to result in a live birth |
Researchers analysed data from the Human Fertilisation and Embryology Authority (HFEA) – consisting of 400,135 IVF cycles that took place between April 1991 and June 2008. They found a strong relationship between live birth rates and the number of eggs retrieved in one cycle.
Live birth rates rose with an increasing number of eggs up to 15, and levelled off between 15 and 20, dropping steadily beyond 20 eggs.
“This is the first study to look at the association between the number of eggs and live births,” said Dr Arri Coomarasamy, a clinical reader and consultant in reproductive medicine and surgery at the University of Birmingham.
“Some smaller studies have reported previously on the association between egg numbers and pregnancy rates, but not live births,” Comarasamy said. “This is also the first study to devise a graph that can be used by patients and clinicians to estimate the chances of a live birth for a given number of eggs.”
The graph – a nomogram – is based on data from 2006-2007. Since live birth rates have steadily been increasing, the researchers used this time frame to create a model based on current practices. The nomogram shows the relationship between the woman’s age, then number of eggs retrieved and the predicted live birth rate.
Coomarasamy believes the nomogram could be used with current methods of measuring a woman’s ovarian reserve – anti-mullerian hormone (AMH) and antral follicle count (ACF) – to work out how much her ovaries need to be stimulated in order to retrieve 15 eggs safely.
“AMH and AFC are not good predictors of live birth rates. If clinicians used AMH or AFC to estimate the egg yield, they can then use our nomogran to convert this estimated number into a predicted live birth rate, the completing a prognostic chain to estimate the chances of what both they and the women want: a live born baby,” said Coomarasamy.
