NEW YORK (Reuters Health) - Limiting the number of embryos used for in vitro fertilization (IVF) would prevent up to 40 newborn deaths in Canada each year, researchers say.
It would also stave off dozens of cases of severe eye and brain damage, and cut the time babies spend in intensive care units by 42,000 days annually, they estimate in the Journal of Pediatrics.
The results reflect the potential reductions in the number of premature twins and triplets — who are at greater risk of health complications — that would occur under a policy of using just one embryo for each attempt to get pregnant via IVF.
During the procedure, eggs are fertilized by sperm outside the body and then transferred to the womb.
Transferring more than one embryo into the mother’s womb is thought to increase her odds of getting pregnant, but it also increases her chances of having multiple babies.
Both Canada and the U.S. currently allow multiple embryos to be implanted during each IVF cycle.
In 2005, 29 percent of IVF pregnancies in Canada were twins and about one percent were triplets, according to the new report.
Without fertility treatments, the rate of twins is about one percent, while triplets occur in just one of every 8,100 births, according to the advocacy organization Multiple Births Canada.
Babies that share the womb have a greater risk of being born early, as do babies conceived via IVF, the authors write.
The study found that if IVF were limited to one embryo for each attempt to become pregnant, there would be just three pairs of twins for every 100 deliveries, and no triplets.
The drop in the number of multiple births would considerably reduce the rate of premature births, and subsequently, the complications that go along with being born early.
For instance, in one year at the researchers’ hospital in Montreal, 75 babies — all either a twin or a triplet and conceived via IVF — were admitted to the intensive care unit between 2005 and 2007.
Twenty of these babies were born extremely prematurely. Six of them died, and five had severe bleeding in the brain.
The team estimated that if the mothers of these babies had had just one embryo transferred, there would have been just eight babies admitted to the intensive care unit.
As a consequence of that drop, babies would spend some 3,000 fewer days in the hospital, for instance, and 2,000 fewer days being fed through a tube.
Across Canadian hospitals, the total cost savings would be about $40 million, the researchers concluded.
Dr. Keith Barrington of the University of Montreal, who led the study, said multi-embryo IVF is too risky to allow it to continue unrestricted.
“If you by chance have a premature baby and are unlucky enough to have that child suffer with complications, that’s one thing,” he told Reuters Health. “But to actually have a procedure that increases the chance of that happening is something that should be changed.”
He and his colleagues also estimated the reduction in complications based on a policy in place in Sweden, in which some mothers are provided with multiple embryos, while most mothers are given just one.
Obviously, the reductions in multiple births and health complications would be less pronounced than with a strict one-embryo policy. But Barrington said that being selective about who receives multiple embryos is a reasonable approach, “because for mothers over 35 years of age, it’s quite clear than the chances of getting pregnant are reduced by single-embryo transfer.”
But not all experts believe a one-embryo policy is the way to go.
“In my opinion, reproductive endocrinologists have to determine who’s the best candidate, instead of mandating it,” said Dr. Kurt Barnhart, a physician at the University of Pennsylvania’s Penn Fertility Care in Philadelphia.
“If you mandate it,” he told Reuters Health, “there are some people who won’t get pregnant at all.”
Barrington said that Quebec has instituted a single-embryo policy for IVF procedures paid for by the government, which has led to a drop in the number of twins and triplets being born.
SOURCE: bit.ly/mJ7JRf, The Journal of Pediatrics, online April 13, 2011.