Unnatural Deselection

The Associated Press reported this yesterday: In a study being published in the New England Journal of Medicine, researchers report that an older woman’s slim chances of conceiving could be further decreased if she opts to have her embryos screened for defects before having them transferred to her uterus.

The screening process involves taking one cell from a developing embryo to look for chromosomal defects and discarding embryos that fail to meet the standard. In the past doctors thought selecting the "best" embryos would increase an older woman's chance of becoming pregnant. (Many of these same doctors, it should be noted, stood to make up to $5,000 for a single screening test.)

The test group consisted of 408 women, ages 35 to 41 who underwent three IVF cycles. Roughly half had embryos screened, and those who opted to do so had a 25 percent success rate vs. the 37 percent rate of those who opted not to screen. One theory is that the biopsy of the cell needed for pregenetic screening harms the embryo development more than was previously thought.