Fifteen Egg IVF Study is Misleading, Says Experts
A new study claiming that doctors should aim to retrieve 15 eggs from a woman's ovaries during an in vitro fertilization (IVF) cycle in order to maximize her chances of a baby has some fertility experts concerned.
15 Eggs Is Best?
The study, published in the medical journal Human Reproduction, examined the relationship between the number of eggs retrieved in an IVF cycle and chances of the cycle resulting in a live birth.
The British researchers used data from over 400,000 IVF cycles that took place in the UK between 1991 and 2008. According to the study's results the live birth rate rose significantly when the number of eggs retrieved in a cycle reached 15, plateaued between 15 and 20 eggs and then declined after 20.
Head researcher on the study Dr. Arri Coomarasamy of Birmingham University says that this is the first evidence to show that 15 is the magic number when it comes to increasing ones chance of a successful IVF cycle.
“Our data show that around 15 eggs may be the best number to aim for in an IVF cycle in order to maximize the chances of a live birth,” says Coomarasamy. Furthermore, he adds, this data can be used to help provide patients and clinicians with more accurate estimations on the probability that a woman will have a successful in vitro outcome.
Experts Question Study Implications
However, despite the seemingly clear-cut results of the study, some fertility experts are concerned about how these results are being interpreted. Norbert Gleicher, MD. Medical Director of a New York IVF and fertility research center explains in a press release that the number of eggs retrieved in an in vitro cycle is only a reflection of how many eggs a patient has in her ovarian reserve. The reserve, he says, is really what determines how successful a woman will be with IVF treatment. “It is not the number of eggs we worry about,” says Dr. Gleicher. “It’s the patient’s ovarian reserve!”
In simple terms, a woman's ovarian reserve a measure of the function of her ovaries. The reproductive potential of a woman is often determined by how well her ovaries are functioning and the amount of eggs that she has available in her reserve that are capable of producing healthy offspring. However, as a woman ages this reserve decreases. Typically, by age 40 all women have a significantly diminished ovarian reserve, although in some women this reserve may decline prematurely.
The study, showing that live birth rates plateaued between 15 and 20 eggs, just simply shows that 15 to 20 eggs retrieved in an in vitro cycle reflects the maximal ovarian reserve at all ages. “If the number of eggs, instead of ovarian reserve, were the true determinant of live birth chances, we could simply stop retrieving eggs when we reach that specified number. This, however, would only increase risks to patients,” says Dr. David H. Barad, Clinical Director of IVF at the Center for Human Reproduction. “Technically, ovaries cannot be stimulated toward production of a specific number of eggs.”
Dr. Gleicher warns that this study is misleading to women about their chances of success with IVF. Women over 40 undergoing IVF, he says in an example, can rarely reach 15-20 eggs in an IVF cycle. Sometimes this can be achieved, however only after undergoing significant medication treatment to stimulate the ovaries. This kind of intense therapy places a woman at risk for ovarian hyperstimulation syndrome – a potentially life-threatening condition.
These fertility experts say that rather than aiming for the magic 15 number of eggs, other indicators of ovarian reserve, such as anti-Muellerian hormone levels, should be used.