BOSTON -- In the five years since the "Octomom" case, big multiple births have gone way down but the twin rate has barely budged. Now, fertility experts are pushing a new goal: one.
A growing number of couples are attempting pregnancy with just a single embryo, helped by new ways to pick the ones most likely to succeed. New guidelines urge doctors to stress this approach.
Twins aren't always twice as nice; they have much higher risks of prematurity and serious health problems. Nearly half of all babies born with advanced fertility help are multiple births, new federal numbers show.
Abigail and Ken Ernst of Oldwick, N.J., used the one-embryo approach to conceive Lucy, a daughter born in September. It "just seemed the most normal, the most natural way" to conceive and avoid a high-risk twin pregnancy, the new mom said.
Not all couples feel that way, though. Some can only afford one try with in vitro fertilization, or IVF, so they insist that at least two embryos be used to boost their odds, and view twins as two for the price of one.
Many patients "are telling their physicians 'I want twins,' " said Barbara Collura, president of Resolve, a support and advocacy group. "We as a society think twins are healthy and always come out great. There's very little reality" about the increased medical risks for babies and moms, she said.
The 2009 case of a California woman who had octuplets using IVF focused attention on the issue of big multiple births, and the numbers have dropped, except for twins.
The Centers for Disease Control and Prevention's most recent numbers show that 46 percent of IVF babies are multiples -- mostly twins -- and 37 percent are born premature. By comparison, only 3 percent of babies born without fertility help are twins and about 12 percent are preterm.
Some European countries that pay for fertility treatments require using one embryo at a time.
The American Society for Reproductive Medicine is trying to make it the norm in the U.S., too. Its guidelines, updated earlier this year, say that for women with reasonable medical odds of success, those under 35 should be offered single embryo transfer and no more than two at a time. The number rises with age, to two or three embryos for women up to 40, since older women have more trouble conceiving.
The one-at-a-time idea is catching on. Only 4 percent of women under 35 used single embryos in 2007 but nearly 12 percent did in 2011. It's less common among older women, who account for fewer IVF pregnancies, but it is gaining among them, too.