The good news is that recent research is showing that doing a single embryo transfer can, in some cases, work as well as transferring multiple embryos.

A study in the March issue of the medical journal Lancet followed 400 patients in the Netherlands who got either a standard IVF drug protocol and had two embryos transferred or got less medication with a single embryo. A year later, the rates of babies born were comparable — 45 percent for the standard group versus 43 percent for the single-embryo group — but the milder treatment with a single embryo naturally cut the rate of multiples, as well as the overall cost.

Findings like these are likely to up the rate of SET (it now makes up just 3 percent of all ART procedures) since doctors can use this information to counter some patients’ serious skepticism about putting in just one embryo.

“The powerful thing is data. When you can show pregnancy rates are the same between single and double [embryo transfers], that’s the thing that convinces them, so patients realize they are not compromising,” says Stillman.

Crucial caveats
There are a couple of caveats, though. For starters, SET doesn’t work the same for all women; success depends a lot on picking the right patient — and the right embryo.

Dr. Mike Soules, a managing partner of Seattle Reproductive Medicine and a past president of ASRM, says the women for whom SET is most likely to end in a healthy pregnancy are those 38 or under with no failed IVF cycle, no history of uterine problems and with at least eight high-quality embryos. (He acknowledges that these are the “top 15 percent” and the ones most likely to get pregnant anyway.)

Interactive Baby-making by the numbers: Stats on women in the workplace, the rate of assisted reproduction, numbers of twins and triplets, and much more.

And embryo quality is key, says Dr. Geoffrey Sher, executive medical director of Sher Institutes for Reproductive Medicine in Las Vegas and the lead author of a January study in the journal Fertility and Sterility. “We found that if we put back a single embryo that was from a chromosomally normal egg … then there was an 87 percent chance that the egg would propagate into a normal embryo.”

That one embryo, he continues, went on to make a healthy baby more than 70 percent of the time in this trial, regardless of a woman’s age — a dramatic improvement over typical IVF success rates of roughly 25 percent — and without any of the risks of a multiple pregnancy.

So how do doctors pick the perfect embryo, the one most likely to grow into a son or daughter? That’s no easy task at this time, but scientists like Sher are working to come up with techniques that will hopefully lead to widespread tests to assess an embryo’s viability.

Kinder, gentler fertility approaches Single embryo transfer isn’t the only less-may-be-more strategy for getting pregnant. Here are some other options: — Minimal-stimulation IVF, in which a woman gets far less ovulation-inducing medication, is being offered by an increasing number of fertility doctors. Success rates are substantially lower, though — just 10 percent to 15 percent, compared with about 25 percent for standard IVF, says the Society for Assisted Reproductive Technology. — Acupuncture, the ancient system of stimulating specific points on the body with super-fine needles may be useful during IVF, perhaps by improving blood flow to the uterus. A 2006 German study of 225 women undergoing IVF compared those who got real versus sham acupuncture and found that nearly 34 percent of the acupuncture group got pregnant, compared with 28 percent of the other group. — Stress reduction is a big part of the burgeoning mind/body approach to infertility treatment. One study showed the strain of treatment to be as high as that of having cancer; other research has found women with lower stress have more success with IVF. “The jury is still out as to whether stress causes infertility, but we do know that infertility causes stress,” says Beth Heller, co-founder of Pulling Down the Moon, Chicago-area yoga studios with a focus on infertility. “There’s a negative feedback loop, where stress can cause depression, it can cause women not to sleep well, to stress-eat, and it can cause marital issues that can impact the sex life.”

Currently, some doctors can use preimplantation genetic diagnosis to rule out genetic disorders such as sickle cell anemia and cystic fibrosis, though the approach is limited for determining the overall health of an embryo because it can't screen all chromosomes.

So researchers are trying to develop other approaches that would allow them to screen all chromosomes or test the culture solution that an embryo is grown in for biochemical markers that indicate good health.

Once it becomes easier, faster, more accurate and less expensive to pick one healthy embryo, choosing whether to do SET will become far less difficult, with better results.

A big part of that shift, says Stillman, is changing how success is defined: “The real measure of the success of an IVF program is the singleton delivery rate, not just the delivery rate.”

Lorie A. Parch is a writer and editor in Scottsdale, Ariz., who has written for Women's Health, Town & Country, Shape, Prevention and Conceive.

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