A push for single births

Fertility doctors are under pressure to reduce the number of twins produced by in-vitro fertilization because dual births are riskier and costlier than singles.

But conservative treatment is a tough sell.

In a way, IVF clinics are feeling the fallout of their own success. Doctors used to routinely put three to six embryos in the womb in hopes that one would grow. Now, the cumulative odds of a baby after three IVF attempts are so good - well over 60 percent - that fewer embryos are needed per try.

In fact, a growing body of international research shows that for nearly a third of attempts, just one high-quality embryo is enough, although the patient may need two or three tries. Adding a second embryo merely boosts the chance - the risk - of twins.

A few European countries, bent on reducing double births, now mandate "single-embryo transfer." And some Australian fertility specialists argue that IVF success should be redefined as full-term, single births.

In the United States, where IVF is usually not covered by insurance and is largely unregulated, the one-at-a-time campaign is just starting to catch on. Fertility specialists' organizations in 2004 revised their IVF guidelines to promote single-embryo transfers. To highlight the practice, the most recent annual clinic success-rate reports now show data on single-embryo use and singleton births.

"I think the ideal outcome of IVF is unequivocally a healthy singleton birth," said reproductive endocrinologist Marc Fritz, chair of the guidelines committee of the American Society for Reproductive Medicine.

The problem is, the nation's 420 clinics and their patients have strong incentives to see twins as ideal.

Each year since 2001, twins have made up about 44 percent of all IVF births in the United States. While the rate seems to have plateaued, it has doubled since 1996, and the actual number of twins keeps growing because more couples are using IVF. In 2005, about 22,000 twins were born.

Twins aren't nearly as dangerous as triplets or higher multiples, which until recently have been the focus of efforts to make IVF safer. But twins aren't just a twofer, either. Compared with singletons, studies show, twins are significantly more likely to be premature, with all the problems that entails.

On average, twins' medical costs before and soon after birth are four or five times more than for singletons, studies show.

Still, the overwhelming majority of twins are fine in the long run, so IVF doctors tend to downplay the dangers.

"The risk of twins, in most of our patients, is an acceptable risk," said Wendy Schillings, a reproductive endocrinologist in Allentown.

Patients, meanwhile, usually consider twins a bonus - a way to double their dream-come-true and end the nightmare of infertility.

"The first office visit," Shillings said, "they tell me: 'I want twins.' "

If twins aren't an explicit goal, maximizing the odds of pregnancy on the first try is.

That's why, in 2003, Leanne and Greg Thomas overruled their IVF doctor.

He recommended transferring two embryos, and freezing five extras for possible future use.

Instead, the Laurel, Del., couple insisted on three embryos for Leanne, then 30. At $12,000 per IVF try, they were going for broke, in more ways than one.

"We didn't have any insurance," said Leanne, who has a metabolic disorder that is a common cause of infertility. "I wasn't comfortable with transferring two embryos because, if it didn't work, I'd always wonder whether we should have done three."

They were thrilled when she got pregnant with twins.

But 29 weeks into what should have been a 40-week gestation, a routine visit with the obstetrician revealed Leanne's birth canal was wide open. No labor pains, no warnings - and no holding off the births.

Amanda and Ashley were delivered 11 weeks early, slightly over three pounds each. They spent six weeks in neonatal intensive care, from which 3.4 percent of twins emerge with permanent handicaps.

"I said, 'I don't care about me; I want to know what's going to happen to these babies,' " Leanne recalled telling the doctors at Christiana Hospital. "They said they didn't know."

Now age 3, Amanda and Ashley are healthy, happy, and, by all measures, normal.

"We were very, very lucky," Leanne said. "Knowing what we know now, we decided to donate our four frozen embryos. We're not pushing our envelope. We're done."

Under the American Society for Reproductive Medicine's revised 2004 guidelines, Leanne would have been a perfect candidate for single-embryo transfer. She was under age 35, trying IVF for the first time, and had enough good-quality embryos to freeze extras. Extras can shortcut another IVF attempt, and cut costs, by eliminating the daily hormone shots and egg-extraction process.

Yet even after her harrowing experience, Leanne can't imagine using one embryo, knowing it might have added months to the ordeal.

"There's no way I would risk it on one, probably not even if I had insurance," she said. "The physical and emotional aspects of IVF are too much of a strain."

Fertility doctors say patients are the biggest obstacle to conservative measures.

"We present data. We beg, plead, and stand on our heads: 'Take a single embryo.' But patients have to make the ultimate decision," said Jay S. Schinfeld, director of the IVF center at Abington Memorial Hospital.

In 2005, women under age 38 had 57,000 IVF tries; fewer than 1,000 were elective single-embryo transfers.

Doctors also stress that they have made strides in avoiding the most dangerous pregnancies. Triplets and higher multiples have declined from a peak of 11 percent of IVF births in 1997 to about 6 percent - 1,350 babies - in the latest clinic reports.

Even so, those reports show vast room for improvement. Nationally, 53 percent of women transferred not one, not two, but three or more embryos in 2004. Even among women under 35, whose youthful ovaries give them an edge, almost a third used three or more embryos.

At international conferences, "we Americans are looked at like cowboys," conceded Larry Barmat, Schinfeld's partner in Abington.

Although doctors don't like to say so, they have an incentive to be a bit aggressive. The more embryo transfers that result in births - multiples or not - the better the clinic's statistics.

"Reporting success in terms of total pregnancy and live birth rates is resulting in increased competition among . . . clinics, with multiple gestation an unfortunate consequence," researchers from the Centers for Disease Control and Prevention wrote in 2004.

As reproductive technology continues to improve, however, it's becoming clear that less is sometimes more. A Finnish study of women aged 36 to 39, published last year in Human Reproduction, found that 42 percent in a single-embryo-transfer group wound up with a baby, compared with only 27 percent who transferred two embryos.

At the University of Pennsylvania's IVF clinic, the number of women under 35 who transferred one embryo in 2005 was . . . zero. None at all.

That should soon change, said Anuja Dokras, the new associate medical director.

Dokras was recruited from the University of Iowa, where avoiding twins is a crusade. For the last three years, Iowa's clinic has given candidates for single-embryo transfer no alternative (except to drive many miles to the state's only other IVF clinic).

"The thinking was, 'If the success rate is the same with one or two embryos, why take the extra risk of twins?' " Dokras said.

Iowa starts "educating" patients the day they walk in. They get a one-page comparison of the risks of twins. They discuss financial and psychological issues. They're told they will use a single, five-day-old embryo only if they're lucky enough to "qualify."

As Iowa's lab director, Amy Sparks, explained: "We present it as, 'Congratulations! Your chances of pregnancy are so good that you only need one embryo.' "

Nearly a third of women under 38 - about 180 patients a year - fall under the mandate. About 70 percent wind up with a baby on their first try. The cumulative success rate is an astounding 86 percent. And the clinic's twin rate has fallen from 40 percent to 20 percent of births.

Penn's twin rate is already a relatively reasonable 25 percent, but Dokras sees opportunity because most patients are transferring three or more embryos.

"Before IVF got better, I think the focus was, 'Let's get our patients pregnant,' " she said. "Now it's, 'Let's minimize the risks of IVF.' "