Detects 77% of aneuploid embryos: PGD may slash miscarriage rate after in vitro fertilization.(Gynecology)

RANCHO MIRAGE, CALIF. -- Obtaining a preimplantation genetic diagnosis using a 9- or 10-chromosome screening panel would detect 77% of embryos with aneuploidy, preventing their transfer and thereby reducing the miscarriage rate in patients undergoing in vitro fertilization by almost 50%, Dr. Ruth B. Lathi reported at the annual meeting of the Pacific Coast Reproductive Society.

Aneuploidy is the leading cause of first trimester spontaneous abortion, an event associated with substantial financial and personal hardship in patients trying to bear children using in vitro fertilization (IVF).

Dr. Lathi and her associates at Stanford (Calif.) University reviewed cytogenetic testing results of the products of conception in infertility patients who suffered first trimester losses over a 4-year period.

Patients in the program were routinely offered dilation and curettage and cytogenetic testing; the sample included results from all who agreed.

Among 134 karyotypes tested, 59% were abnormal, the vast majority due to autosomal trisomies. Structural rearrangements, monosomy X, triploidy, and tetraploidy also were found.

The most common sites of aneuploidy were chromosomes 15 and 16, although problems on chromosomes 21, 22, and 18 also were frequent.

Investigators compared the detection rates of aneuploidy by panels employed by various national laboratories that specialize in preimplantation genetic diagnosis (PGD) using fluorescent in situ hybridization (FISH). These panels scan for abnormalities on the following chromosomes: