New Report Bolsters Support For Preimplantation Genetic Diagnosis (PGD) To Improve Pregnancy Rates In Assisted Reproduction

Main Category: Fertility
Also Included In: Genetics
Article Date: 08 Aug 2010 - 0:00 PDT

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A newly published report underscores the importance of technology and skilled technique in the practice of preimplantation genetic diagnosis (PGD). PGD has been a hotly debated topic in recent years due to the inconsistent conclusions from numerous trials.

The paper, published in the July issue of Fertility and Sterility, identifies numerous factors that contribute to the procedure's success. Data show that PGD success appears to correlate with access to the appropriate technology and the level of skill and technique used by the embryologists.

"Our analysis of available research shows that clinics using optimal methodology, highly skilled technicians and the most advanced chromosomal assessment techniques have consistently shown an improvement in assisted reproductive technology results with PGD," said Santiago Munne, Ph.D., founder of Reprogenetics and one of the nation's leading experts on PGD. "PGD remains a viable option for many couples who are at risk of passing on certain genetic diseases to their children or who have been unsuccessful with assisted reproduction to help increase their chance of having a healthy baby."

In his review, Dr. Munne identified that widely varying biopsy and chromosome analysis procedures were used, leading to conflicting results. Additionally, poor training and limited experience in these delicate procedures may also contribute to reduced embryo implantation following PGD.

According to Dr. Munne, the formula for successful PGD includes: Identifying the appropriate patient by considering maternal age and evaluating the number of embryos available, using an experienced laboratory with trained scientists reduces the risk of not obtaining a result, taking a biopsy of a single cell from the embryo, processing of the cell appropriately, analyzing a minimum of eight important chromosomes as well as working with a PGD laboratory that has an error rates below 10% with extensive experience and showing positive outcomes in PGD.

The technique used to analyze the extracted chromosomes may play an important role in embryo selection. Array comparative genome hybridization (array CGH) is a newer technique capable of accurately determining total or partial abnormalities affecting any of the 24 different types of chromosomes, compared to more traditional FISH testing which analyzes just 5-12 chromosomes. Data presented at the last American Society of Reproductive Medicine meeting demonstrated that using CGH analysis resulted in a highly statistically significant increase in implantation rates in women with an average age of 38 and with one to 10 prior failed IVF cycles.

About PGD

In PGD, embryos created through in-vitro fertilization are tested for chromosomal abnormalities prior to replacement in a woman's uterus. This process allows the reproductive endocrinologist to select only chromosomally healthy embryos for replacement with the goal of increasing the chance of successful implantation, reducing spontaneous abortion, reducing the chance for a fetus to have a chromosomal abnormality and in some cases improving delivery rates for assisted reproduction.

Chromosome abnormalities are the primary cause of miscarriage and more than 50%. This percentage increases with maternal age, and studies have shown that 82% of embryos from woman 40 years and older will be chromosomally abnormal.

Source:
Reprogenetics

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