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Women Are Turning to 'Abnormal' Embryos for a Last Chance at Pregnancy

Photograph by Twenty20

If you feel like you're at the end of your IVF rope, there might still be a last chance to get pregnant.

Women who have gone through in vitro fertilization (IVF) are familiar with the ups and downs of the costly and sometimes heart-rending process. You inject yourself with hormones and have your eggs extracted to have them fertilized by mixing them with sperm in the laboratory. The most viable embryos are then transferred back into the womb in hopes of a healthy pregnancy. Many people also opt to have the embryos screened before the transfer to check if the embryos are chromosomally normal, known as Pre-Implantation Genetic Screening (PGS), which can come at higher material and emotional costs.

But what if this whole idea of weeding out chromosomally abnormal embryos is scientifically incorrect? What if these "abnormal" embryos are actually viable and can lead to healthy pregnancies and children?

A recent study performed by the Genoma group and European IVF Center in Rome are making waves about this already controversial topic. Researchers found that among mosaic embryos, or embryos with a mix of normal (euploid) and abnormal (aneuploid) cells, many still have the potential to implant in the uterus and develop into chromosomally healthy newborns.

The researchers looked at 73 women who had no chromosomally normal embryos that would typically be transferred. They did, however, have mosaic embryos, which could be transferred. The women who chose mosaic embryos with a high percentage of abnormal cells gave birth 16.7 percent of the time, while 10 percent of them led to miscarriages. Of those women transferring mosaic embryos with a lower percentage of abnormal cells, the birth rate was 39.5 percent and the miscarriage rate was 7 percent. That's a huge statistical possibility for women who already feel as if they have no chance. For women older than 42, almost 90 percent of the embryos produced are aneuploid.

Sometimes embryos that have abnormal chromosomes might self-correct and result in a normal fetus, perhaps because aneuploid cells have a growth disadvantage and get eliminated, or because these abnormal cells may be isolated in the placenta, where it might not affect the developing fetus.

New York magazine recently ran a feature on aneuploid cells and followed the stories of women who had successful births despite clinics thinking their embryos would not be viable. The piece brought up criticisms of PGS, including the fact that it doesn't always accurately reflect the chromosome status of the embryo. Like a soccer ball, depending on where you biopsy, sometimes you may hit a white part or a black part, or right in the middle of both. Where you land can lead you to think the embryo is normal or abnormal or a mix of both.

Jeffrey Braverman, who runs IVF clinics in Manhattan and Long Island, told New York magazine that the lowest possible number of women that lost the opportunity to have a child due to the inaccuracy of PGS would be 20,000 over the past two decades. Other estimates show a much higher number, at about 13,000 per year.

But those who are hoping to transfer abnormal embryos should consider a few risks. There is still a possibility of miscarriage or even a genetically abnormal child. With it comes emotional trauma of not knowing whether the pregnancy is normal, as a prenatal test doesn't occur until the 10th week, and the hard decision that may come if the pregnancy ends up being abnormal.

For Monica Halem, one of the women interviewed by New York magazine, the decision to use a supposedly abnormal embryo was worth it: What others might have thrown away became a healthy baby girl.

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