Screening IVF Embryos Ineffective for Older Moms

European study finds procedure results in lower live birth rates

By Serena Gordon
HealthDay Reporter
Wednesday, July 4, 2007; 12:00 AM

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WEDNESDAY, July 4 (HealthDay News) -- Routine screening of the embryos of older mothers won't increase their chances of successful pregnancy after in vitro fertilization, and might even have the opposite effect, a new Dutch study suggests.

In the July 5 issue of the New England Journal of Medicine, European researchers report that the live birth rate for older women who had preimplantation screening as part of the in vitro fertilization (IVF) procedure was 24 percent compared to 35 percent in women who had IVF without preimplantation screening.

"Preimplantation genetic screening is meant to increase the chance to achieve a live birth," said Sjoerd Repping, director of the IVF laboratory at the Center for Reproductive Medicine at the Academic Medical Center in Amsterdam. Instead, Repping said, "PGS significantly reduces the chance of an ongoing pregnancy in women of advanced maternal age."

Preimplantation genetic screening is done by removing one or two cells from an embryo before it's implanted in the mother's uterus. Those cells are then tested for certain known abnormalities, such as cystic fibrosis, Huntington's disease and sickle cell anemia. The procedure adds between $3,000 and $5,000 to an IVF attempt, but for people at high risk of transmitting a genetic abnormality, it can help assure a healthy pregnancy.

"Preimplantation genetic diagnosis is not without risk, however," wrote Dr. John Collins from McMaster University in an accompanying editorial. On average, live birth rates are lower after preimplantation screening, according to Collins.

Dr. Jamie Grifo, director of the division of reproductive endocrinology at the New York University School of Medicine, said he believed the act of taking a biopsy from the embryo to remove the cells for genetic testing does reduce the pregnancy rate "to some extent."

But, he added, in certain high-risk women, the benefits of knowing that you're not transmitting a devastating genetic illness to your offspring outweigh the risks of the procedure.