Mr. Bush's ambivalence about research involving embryos
Mr. Bush publicized himself today with a group of children who had been adopted as embryos. He urged his people to support embryo adoption rather than using embryos for stem cell research, so I decided to do the math.
The Rand Corporation's 2003 report does a lot of the math and is widely quoted. Their researchers estimate that 400,000 embryos have been frozen and stored over the past 25 years in the U.S. (as of 2003). Of these, however, only 2.8% have been donated for research. The majority are being reserved for future attempts at pregnancy. So 11,000 are available for research.
But the Rand report points out that the best embryos have already been used in pregnancy attempts, so these are not the best embryos the patients produced. And some embryos have been stored since the late 1970s, when freezing technology wasn't well developed. So only 65%, or 7334, embryos are estimated to survive freezing and thawing, and only 25%, or 1,834, embryos are estimated to continue to develop.
Now let's be very optimistic and say that all 1834 surviving embryos are good enough to implant in healthy, willing women— the vessels. Now not all of these embryo transfers are likely to "take"--that is, to stick the landing. According to the American Pregnancy website, as many as "48% of women using donor eggs will experience pregnancy, however approximately 15-20% of women will lose the pregnancy through miscarriage." Let's continue to be optimistic and say that 48% of these embryos will implant—that is, stick to the vessel—and that only 15% of the vessels will miscarry (we'll also assume that only one embryo was transferred to each vessel). That would mean as many as 748 pregnancies.
The other 10,252 embryos wouldn't survive the process of thawing and embryonic transfer and drug-induced pregnancy.
When embryo implantation works, it's a miracle. But to develop these successful techniques, doctors failed many times, and each failure involved the loss of embryos. Bush's political stance, i.e. his opposition to research involving the loss of embryos, would have blocked the research that produced the children standing with Bush today.
The Rand Corporation's 2003 report does a lot of the math and is widely quoted. Their researchers estimate that 400,000 embryos have been frozen and stored over the past 25 years in the U.S. (as of 2003). Of these, however, only 2.8% have been donated for research. The majority are being reserved for future attempts at pregnancy. So 11,000 are available for research.
But the Rand report points out that the best embryos have already been used in pregnancy attempts, so these are not the best embryos the patients produced. And some embryos have been stored since the late 1970s, when freezing technology wasn't well developed. So only 65%, or 7334, embryos are estimated to survive freezing and thawing, and only 25%, or 1,834, embryos are estimated to continue to develop.
Now let's be very optimistic and say that all 1834 surviving embryos are good enough to implant in healthy, willing women— the vessels. Now not all of these embryo transfers are likely to "take"--that is, to stick the landing. According to the American Pregnancy website, as many as "48% of women using donor eggs will experience pregnancy, however approximately 15-20% of women will lose the pregnancy through miscarriage." Let's continue to be optimistic and say that 48% of these embryos will implant—that is, stick to the vessel—and that only 15% of the vessels will miscarry (we'll also assume that only one embryo was transferred to each vessel). That would mean as many as 748 pregnancies.
The other 10,252 embryos wouldn't survive the process of thawing and embryonic transfer and drug-induced pregnancy.
When embryo implantation works, it's a miracle. But to develop these successful techniques, doctors failed many times, and each failure involved the loss of embryos. Bush's political stance, i.e. his opposition to research involving the loss of embryos, would have blocked the research that produced the children standing with Bush today.
posted by Lynn Holleman Rudloff | 10:14 PM
0 Comments:
Post a Comment
<< Home