IVF Embryo Screening: Pregnancy Boost?
Researchers Say Technique Lowers Pregnancy Chances for Women Having in Vitro Fertilization
WebMD News Archive
Criticism of the Study continued...
"This research team is inexperienced," says Santiago Munne, PhD, a
member of the board of directors for the Preimplantation Genetic Diagnosis
International Society, a Chicago-based organization that coordinated research,
education, and training in the technique.
Munne and other critics say that inexperience affected the results. For
instance, 20% of the embryos tested came up with "undetermined"
results, with the researchers unable to term them normal or abnormal.
"Experienced centers typically have a 5% indeterminate rate," Munne
The undiagnosed embryos were transferred to the women, resulting in an
implantation rate of 6% compared with the higher 14.7% implantation rate in the
group of patients whose embryos did not have biopsies, he says.
"In our study, all biopsies were performed on the third day after
insemination, which is very normal in the case of preimplantation genetic
screening," Mastenbroek responds.
"Our results are in line with all other data available in the scientific
literature," he adds. "A beneficial effect in terms of ongoing
pregnancy has never been shown for PGS. Lower ongoing pregnancy rates have been
shown before, but this outcome was significant in our trial since this is the
largest randomized trial available today."
Now, he says, his team is investigating why the technique was
In an editorial accompanying the study, John A. Collins, MD, a physician at
McMaster University in Hamilton, Ontario and Dalhousie University, Halifax,
Nova Scotia, Canada, puts the results in perspective: "The results suggest
that for every nine women who are 35 to 41 years of age who plan three cycles
of IVF or IVF and intracytoplasmic sperm injection, there will be one more live
birth if pre-implantation genetic diagnosis for [abnormalities] is not
In an email interview, Collins tells WebMD that the new study results are
"convincing most people in the field that PGS has no value in screening
infertile women over 35 undergoing IVF."
In his editorial, Collins advises that the preimplantation screening not be
done solely due to a woman's age.