The largest study to date of pregnancies and subsequent births of children conceived after undergoing preimplantation genetic diagnosis (PGD) was published in the January 2010 issue of the journal Human Reproduction. This study attempts to determine whether removing a cell or two from an embryo to screen it for inherited conditions or genetic abnormalities can, in itself, impair the health of the subsequent pregnancies or births. This research was summarized in a Dec. 23, 2009 article in Science Daily.
The current study looks at the health of all pregnancies, deliveries and babies born after preimplantation genetic diagnosis and screening (PGD/PGS) at one Dutch infertility clinic between 1992 and 2005. In all, 581 babies were examined at two months old and questionnaires were sent to parents and physicians at the time of conception and delivery. The PGD/PGS babies were compared with a control group of IVF/ intracytoplasmic sperm injection (ICSI) children to determine if any differences in outcomes were related to the embryonic biopsies required in PGD and not to other standard IVF/ICSI procedures.
There was no statistically significant difference in outcome between the two groups in the gestational ages at delivery, birth weights and major malformations. There was no difference in the numbers of deaths around the time of birth between PGD/PGS and ICSI babies if they were born as a result of singleton pregnancies. "[T]he health of the singleton children born after embryo biopsy for PGD is similar to the health of singleton children born after IVF/ICSI." However, there were five times more perinatal deaths after multiple pregnancies in the PGD/PGS babies compared to the ICSI babies (11.73% versus 2.54%) "A point of concern in this study was the multiple PGD/PGS children being more often premature and of low birth weight."
In the editorial that accompanied the study in Human Reproduction, Dr. Joe Leigh Simpson, Professor of Human and Molecular Genetics and Professor of Obstetrics and Gynecology at the Wertheim College of Medicine, Florida International University, USA, wrote: "PGD is not the purview of amateurs or the inexperienced, nor is any technical procedure. Inferential data suggest that less than fully experienced embryologists or diagnosticians may do more harm than good when performing PGD, especially PGD aneuploidy testing."
Although this is the largest study to date, only 581 children were studied., and the data was only collected through two months of age. Long term studies that follow children for many years are needed to fully assess the risks of PGD/PGS.