Safety of Day 5 Biopsy

Some dr's tout the 5 day biopsy as being the wave of the future in PGD since you don't have to tamper or extract a cell from what will become the fetus. My question is - is there any way the fetal membranes or placenta could be damaged by extracting cells for a day 5 biopsy that will affect the development or cause defects eg neurological or other in the developing fetus -- how do we know that it the biopsy wont affect the fetus or the nutrition provided to the fetus. What do they mean when they refer to fetal membranes as being biopsied in a day 5 biopsy?
Thanks so much!

Hi bows&ribbons,
There are a couple of things that may reassure you about the day 5 biopsy. First, the 10-20 cells that are removed from the embryo's trophoblast are a small percentage of the whole embryo and are selectively removed from the cell pool that would develop into the future placenta (the fetal membranes in the earliest stages) , not the fetus itself. Also, to date, I am unaware of any clinical concerns regarding fetal health arising from the day 5 biopsy procedures. These early cells are easily replaced by the massive cell proliferation that occurs in the days and weeks after the biopsy. Nature has plenty of redundancy built in because some cells die off naturally anyway so the embryo has to be tolerant of this possibility.
Hope this helps,
Carole