Multiple Births From In-Vitro Targeted

A major medical group has issued new guidelines aimed at limiting the number of multiple pregnancies that result from in-vitro fertilization.

The American Society for Reproductive Medicine announced the changes at its meeting this week in New Orleans.

As The Early Show medical correspondent Dr. Emily Senay explained Tuesday, when women who can't conceive on their own try to get pregnant through in-vitro fertilization, it's common for fertility clinics to implant multiple embryos. The logic is that if you implant more than one, the chances of any one of them taking hold and resulting in a successful pregnancy improves.

But according to the March of Dimes, implantations of that nature result in multiple births more than a third of the time. More than half of all twins and nearly all triplets are born prematurely. And premature birth can lead to permanent disabilities, even death. Health risks to the mother also increase.

So, says Senay, the ASRM now suggests that women under 35 receive no more than two embryos at a time, and that doctors should consider implanting only one. The numbers recommended under the guidelines rise with the woman's age, to compensate for the greater difficulty that older women have achieving pregnancy. Once women are over 40, these guidelines call for them to receive up to five embryos.

The guidelines aren't written in stone, Senay stresses. It's a very individual matter. Different women have different physical characteristics, including the quality of the embryos that are harvested to attempt fertilization.

The guidelines are recommendations, to minimize the number of multiple pregnancies wherever possible, while still giving women a chance to conceive that they might not otherwise have.

Unfortunately, Senay points out, we're still not at the stage where doctors can look at a single embryo and be sure it will implant successfully, so multiple implantations will continue, within the guidelines.

Senay also told of researchers at the University of Southern California that had good news for older women. The researchers found that women giving birth beyond the age of 50 exhibit no more of the stress associated with parenthood than women 10 and 20 years younger.

These women were asked how they were doing when their kids were an average of 3 years old. Some of the women surveyed had kids as old as 12. And the consensus was they felt they were doing fine.

But, Senay noted, having kids at 50 or older isn't quite the same as when women are younger. For instance, there's a greater risk of prenatal complications, including high blood pressure and gestational diabetes during the pregnancy.

But once the child is born, these older women reported that the physical and psychological burden of raising their children was no harder than that on younger mothers.