15 Is Ideal For Egg Retrieval

The latest IVF research published online in May 2011 in Human Reproduction shows that to achieve the best results doctors should only retrieve 15 eggs in a single cycle to ensure your chances of a successful pregnancy through IVF.

Research Study

A study by the European Society of Human Reproduction & Embryology, (ESHRE) analysing over 400,000 IVF cycles carried out in the UK, shows that doctors should only try to retrieve just 15 eggs at any one time for the best IVF results.

Researchers at the University of Birmingham, Department of Reproductive Medicine & Surgery analysed over 15 years of IVF data supplied by the Human Fertilisation and Embryology Authority (HFEA). They created a mathematical model called a nomogram, which showed a relationship between a woman's age, the number of retrieved eggs and the number of predicted births. They discovered that there is an optimum number of eggs to retrieve. According to Dr Coomarasamy's research team, "...existing data suggest that the numbers of embryos frozen after a fresh IVF cycle are not enhanced by retrieving more than 18 eggs,". In fact retrieving more than 20 eggs puts the woman at a high risk of developing OHSS (ovarian hyperstimulation syndrome).


A mild to moderate case of OHSS can cause pain, swelling, nausea or vomiting but OHSS can sometimes have serious life threatening consequences. By combining the current anti-mullerian hormone (AMH) and antral follicle count (AFC) tests with the researchers' nomogram mathematical model, fertility specialists will be able to work out the correct amount of ovarian stimulation needed to collect 15 eggs and help avoid OHSS.

Age Counts

It is well known that age makes a difference to your ability to get pregnant. This data underlines that the younger you are the better the success rate of the IVF treatment. Women aged 18-34 have a success rate of 40% with IVF, which drops to 36% for women between 35-37. The success rate drops to 27% for women aged 38-39, while women over 40 have only a 16% chance of success!

Canadian Research

Other research, from the University of Montreal, shows that having multiple embryo transfers also reduces your chance of having a healthy baby. Not only are there more likely to be complications with having a multiple pregnancy, but the babies themselves tend to have more problems. These can be anything from low birth weight, being born prematurely or even serious long-term health problems like cerebral palsy.

Single Embryo Transfer (SET)

The HFEA is encouraging fertility clinics to reduce the standard number of embryos transferred to a woman to maximise her chances of a successful pregnancy. Instead of transferring two embryos, the HFEA is recommending that women who have the highest chances of getting pregnant with IVF, i.e. those under 37, have only one embryo transferred. This strategy, which has been in place since 2007, has succeeded in reducing the number of multiple births while at the same time maintaining women's overall chance of having a baby through IVF. At present, due to the disparity in NHS funding throughout the country, many NHS Primary Care Trusts (PCT) only allow one cycle of treatment on the NHS. This makes women reluctant to opt for the more viable SET, preferring instead to risk having a multiple pregnancy.

What A Difference A Year Makes

If you are looking into IVF treatment don't wait around if you are in your thirties. Remember this research shows that a year or two really does make a difference to your chances of having a baby as you get older.

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