Studies Examine Risks Of IVF Procedures; New Embryo 'Viability' Test

Main Category: Fertility
Also Included In: Pediatrics / Children's Health;  Women's Health / Gynecology
Article Date: 11 Jul 2008 - 8:00 PDT

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Researchers on Tuesday presented two studies at the annual conference of the European Society of Human Reproduction and Embryology in Barcelona, Spain, providing evidence that infants conceived through in vitro fertilization might be as healthy as infants conceived naturally, the AP/International Herald Tribune reports. According to the studies, IVF treatment and the freezing of embryos do not significantly increase the risk of medical problems for infants born from the treatments, which was previously thought to be linked.

In one study, Karin Middelburg of the University Medical Center Groningen in the Netherlands and colleagues compared more than 120 infants conceived using IVF with 450 infants conceived naturally, as well as with 90 infants born to couples with fertility problems who spontaneously conceived while waiting for fertility treatment. The researchers assessed the infants' brain development when they were several months old by observing motor skills -- such as waving hands, making fists or kicking feet.

The researchers found that infants conceived using IVF moved as well as infants spontaneously conceived to couples waiting for infertility treatment, which indicated that artificial reproductive techniques are not the cause of any early developmental problems, Middelburg said. In addition, there were no differences in abnormal movements between the IVF conceived infants, compared with the naturally conceived infants, the study found.

In another study presented at the conference, Anja Pinborg of the Copenhagen University Hospital Rigshospitalet in Denmark and colleagues examined the difference between infants born from frozen embryos and those born from a fresh embryo transfer (AP/International Herald Tribune, 7/8). The researchers compared data from Danish national registries of 1,267 infants born in Denmark from 1995 to 2006 from frozen embryos with nearly 18,000 infants born from fresh embryo transfers during the same time, Reuters reports.

The study found that infants in the frozen embryo group weighed an average of about 200 grams more at birth than the infants in the fresh embryo group. In addition, researchers found that the percentage of preterm births and low birthweight infants was lower in the frozen embryo group. They also found no increased risk of congenital birth defects among infants born from frozen embryos, and those infants spent less time in neonatal intensive care units (Kahn, Reuters, 7/8).

Pinborg said that it is highly unlikely that freezing improved the health of the embryos, adding that the outcomes could be explained because patients who freeze embryos generally are young women with a good prognosis. According to London's Times, the findings are important because women undergoing IVF are increasingly encouraged to use one fresh embryo to avoid multiple births and to freeze any other embryos produced in the process for later use. "These findings are reassuring," Pinborg said, adding, "If our results continue to be positive, frozen embryo replacement can be accepted as a completely safe procedure, which can be used even more frequently."

New Embryo 'Viability' Test Could Improve IVF Success Rate up to 15%

In related news, Denny Sakkas and colleagues from Yale University told the conference that a new "viability index" for selecting embryos to use in IVF treatments can increase the success rate by 10% to 15%. According to the Times, the test can predict which IVF embryos will implant into the womb up to 70% of the time.

Researchers said that the technology, known as metabolomics, could become a routine part of fertility treatment. According to Sakkas, "The other side of IVF is that we probably fail to get patients pregnant about two thirds of the time we do an embryo transfer. One of the reasons is we're not that good at picking the best embryo we have available." He said the viability index is "not going to make a bad embryo good, but it should help us to tell them apart. This definitely could make the difference between people getting pregnant or not" (Henderson, Times, 7/9).

Traditionally, physicians decide which embryos have the best chance of implanting in the womb by examining them through a microscope to see how well they are growing, London's Guardian reports. The new technique removes fluid from the embryo's culture medium and shines infrared light through it to measure the embryo's metabolism, revealing levels of compounds such as glucose that have been used or excreted by embryos.

To determine the efficacy of the test, Sakkas and colleagues tested the culture media of more than 1,000 embryos after they had been implanted in women. The researchers found that those with the highest fitness scores were more likely to have resulted in a pregnancy, with implantation rates increasing from 26% to 39%. According to the Guardian, the equipment for the tests costs about 10,000 British pounds, or about $19,700; however, the cost for a single test is expected to be considerably cheaper (Sample, Guardian, 7/9).

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