BioEd Online

Doctors should hold off from using experimental fertility treatments to bypass the menopause, warned a report released yesterday at the annual meeting of the American Society for Reproductive Medicine (ASRM) in Philadelphia.

The report was drafted because of research advances over the past few years showing that women's eggs and ovarian tissue can be frozen and reused at a later date. These raise the prospect that women might one day routinely freeze their tissue in order to extend their fertile years - or even bear children after the menopause.

But these methods "are by no means ready for prime time," says Mark Fritz of the University of North Carolina, Chapel Hill, and the head of the ASRM committee which advises members on clinical practice. Fritz said that doctors should collect far more data on the health of children born through these methods before their widespread use.

Experimental treatments

A women's fertility is thought to decline from puberty onwards and more steeply from her thirties, as eggs are either ovulated, die or deteriorate in quality. In some cases, women with cancer and other illnesses are rendered infertile much earlier in life, when their eggs are damaged by harsh chemotherapy or radiotherapy.

There are now several ways to avoid this damage, all still in the experimental stages. One is to freeze oocytes - immature eggs - when they are young and healthy for later use in in vitro fertilization (IVF). Doctors are still figuring out how to do this reliably without the formation of damaging ice crystals within the eggs, and there have been fewer than 100 live births using this method. At least two US companies, however, already offer women the chance to freeze their oocytes.

Another option on the horizon is to remove and freeze entire slices of ovarian tissue containing many eggs, and reimplant them at a later stage. Last month, doctors in Belgium announced the birth to a former cancer patient of the first baby produced using this technique¹, although doubts have been expressed over whether the egg involved in the baby's conception definitely came from the reimplanted ovarian tissue.

The ASRM report, which is also published online this month in Fertility and Sterility², agrees that these techniques should be offered, under careful supervision, to female cancer patients or others who will be rendered infertile by medical treatment and who have few other options if they want to bear children.

But before they are offered to otherwise healthy women, the committee recommends that far more data be gathered on whether women experience any health effects and if children suffer an increased risk of abnormalities or long-term health problems.

"The worldwide experience is simply insufficient at this time," Fritz says. The ASRM guidelines are not binding, but those in the field say that most US fertility clinics are expected to abide by them.

Ethical concerns

One or two studies involving 100-200 patients would give a fair idea of the success rate and safety of these techniques, says Kutluk Oktay at the Weill Medical College of Cornell University in New York, who was involved in drafting the report and has been pioneering the method of freezing ovarian tissue. But there would be no guarantees, he cautions; there are still safety concerns about IVF, more than 25 years after its introduction.

Even if the techniques are found to be safe, some people may raise social and ethical objections to women bearing children in their 40s, 50s and 60s. The prospect of grey-haired mothers cuddling newborn babies raises questions, for example, about whether women would be able to care for their offspring in their old age.

Just because men can father children throughout their lives does not mean that it is a good idea for women too, bioethicist Leon Kass of the University of Chicago, Illinois, said at the meeting. "The meaning of this [technology] is profound," he said. "We should think long and hard about it."