How Many Is Too Many?

With other fertility treatments, preventing multiple births is a much less exact science. Using fertility drugs, a woman often produces two, three or four eggs per month instead of one, according to Levy. Doctors can use ultrasound equipment to look at the follicles (fluid-filled spaces within the ovaries that contain eggs) and see how many have grown larger. Usually, only the large ones release an egg -- but not always. One patient at Shady Grove recently showed one big follicle and two small on her ultrasound, but she wound up with triplets.

If the ultrasound shows too many enlarged follicles, Levy explains, he'll recommend a patient cancel the insemination that month, because the chances of multiple gestation are too high. The women are also warned not to have unprotected sex. Of course, not everyone listens. "If you've got someone with 10 follicles, most will see the logic" in not proceeding with the pregnancy attempts that month, says Levy. Smaller numbers take more persuasion.

The Worst Decision

One of the most upsetting scenarios in fertility treatment is when a woman so many embryos actually "take," i.e. implant themselves in the uterine wall, that both the mother and all her babies are at risk of serious health problems. (What's considered risky varies both by the physician and by the woman's health, but triplets seems to be the point where most fertility doctors start worrying.)

In those cases, recommended treatment is often a "reduction" of the pregnancy at 11 weeks. In this procedure, the doctor injects potassium into one or more of the fetuses. The potassium stops the fetal heartbeat, and the fetus is reabsorbed.

"It's a selective abortion, really," said Levy, "but it makes the chances of having a healthy baby far greater."

Not only does such a procedure pose an ethical dilemma for many prospective parents, but it also heightens risks. Reduction carries about a 5 percent chance of losing the pregnancy altogether, according to Levy.

The Owens' first perinatologist urged them to have her pregnancy reduced to twins.

"It was just terrible," Lisa Owen recalled of the meeting, where the doctor was adamant that there was nothing she could do to prevent preterm labor and other complications. Owen and her husband walked out the door and never returned.

Marie and Bob Duncan were also told that reducing their pregnancy from triplets to twins would lower the risk of complications. They declined a reduction as well.

If fertility specialists can prevent the multiple gestations to start with, then parents won't be faced with that decision.