Preimplantation Genetic Diagnosis Reduces Older Women's Chances Of Pregnancy

Preimplantation Genetic Diagnosis

Using preimplantation genetic diagnosis to screen for potential birth defects reduces the likelihood of an older woman becoming pregnant through in vitro fertilization by one-third, according to a study published Thursday in the New England Journal of Medicine, the Los Angeles Times reports. PGD involves removing a single cell from a three-day-old embryo to test for potential birth defects and then implanting the embryos most likely to result in a healthy infant, according to the Times.

Sebastiaan Mastenbroek of the Academic Medical Center at the University of Amsterdam and colleagues enrolled 408 women ages 35 to 41. Half of the women received IVF with PGD and the other half received IVF without PGD. All of the women in the study went through as many as three IVF cycles, the Times reports (Maugh, Los Angeles Times, 7/5). Among the women who received PGD, 25% reached the 12th week of pregnancy, compared with 37% of the women who did not receive PGD. The birth rate was 24% among women receiving PGD and 35% among women not receiving PGD, the study found (Armstrong, Wall Street Journal, 7/5).

According to the Times, only a few thousand PGD procedures are performed annually, although some researchers say the procedure has been increasing by as much as 30% per year (Los Angeles Times, 7/5). About seven in 10 fertility clinics nationwide offer PGD to women undergoing IVF at a cost of $3,000 to $5,000, according to the Journal (Wall Street Journal, 7/5).

The study did not examine why PGD reduces women's chances of pregnancy, London's Independent reports. According to Mastenbroek, it is possible that PGD "hampers the potential of an embryo to successfully implant." According to the Independent, PGD also might not identify all chromosomal abnormalities, leading to possible implantation of embryos with abnormalities.

Reaction

The researchers recommended that PGD should not be offered routinely to women undergoing IVF (Connor, Independent, 7/5). The study "rings the death knell" for using PGD to routinely screen older women, Richard Scott, founder of the IVF clinic chain Reproductive Medicine Associates, said. However, the procedure is still recommended to test for specific genetic defects that the mother and father are known to carry, the Times reports (Los Angeles Times, 7/5).

John Collins, a professor at McMaster University, in a NEJM editorial accompanying the study wrote that PGD "appears to do no more than interfere with the natural screening and selection process." Collins added that the procedure should not be targeted toward older women. Kathy Hudson, director of the Genetics and Public Policy Center at Johns Hopkins University, said that more research is needed into the effectiveness of PGD, adding, "The question is: Are these results truly generalizible to other clinics?" (Wall Street Journal, 7/5).

Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily Women's Health Policy Report, search the archives, and sign up for email delivery at kaisernetwork.org/email . The Kaiser Daily Women's Health Policy Report is published for kaisernetwork.org, a free service of The Henry J. Kaiser Family Foundation. © 2007 Advisory Board Company and Kaiser Family Foundation. All rights reserved.

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