When Two (or More) Become One: Selective Reduction for Multiple Births

Aug. 15, 2011 — -- After years of trying to conceive, Dr. Kelly Ross was stunned to discover that she was pregnant with not just one, but three babies. The long-awaited news "I'm pregnant" now came with a mixed bag of emotions and concerns.

"I never thought I'd be in that position. All of a sudden I found myself with three babies," says Ross, who is the director of pediatric hospitalist medicine at Missouri Baptist Medical Center. Though she had knowingly transferred three embryos during her in vitro fertilization, the chances of all of the embryos taking was only about 3 percent, so Ross never even considered the possibility that she would have to deal with triplets.

"It was the longest, scariest pregnancy," says Ross.

Increased use of in vitro fertilization techniques has made Ross's situation increasingly common. Given the high cost and failure rate of fertility treatments, some couples try to increase their chances of getting pregnant by using multiple embryos and end up facing an unexpected challenge of twins, triplets, or higher multiples -- a challenge some feel they cannot handle, emotionally or financially.

There is a way out of this challenge, but it is one that is seldom discussed among mommies-to-be: selective reduction.

In cases of high multiple pregnancies, doctors will often recommend selective reduction for purely medical reasons. Early in the pregnancy, one or more of the fetuses are aborted from within the womb to increase the likelihood that the remaining babies (and the mother) will survive and thrive. There are numerous health concerns to both mother and infants associated with carrying multiples. Thus for decades obstetricians have offered the option of reducing down to twins, which tend to have safer outcomes. This procedure can only be done with fraternal twins, as identical twins share a placenta and cannot easily be separated.

In the past years, however, some obstetricians and their patients have turned to selective reductions even in the case of twins -- not necessarily for medical reasons, but because the couple does not feel emotionally and/or financially prepared to have two babies when they had planned to have just one.

Fertility message boards such as fertilitythoughts.com are filled with parents-to-be discussing the moral dilemma of reducing to singletons, with many couples admitting that they reduced to one infant simply because they only wanted one.

New York City obstetrician and leading expert in selective reduction, Dr. Mark Evans, says that reductions from twins to a single fetus make up about 10 percent of the reductions he performs in his office, and that number is slowly increasing.

Evans wrote the recommendations on selective reductions 25 years ago, but at time, he advocated for reductions only down to twins, barring extenuating circumstances.

"The rationale was that we knew that we could take care of twins and have good outcomes, and we were generally seeing couples with no kids. So parents often wanted two or more kids ultimately anyway," says Evans.

But in 2004, Evans published a paper that overturned his past recommendations, arguing instead for the safety of reducing to singletons, even if the original pregnancy was only twins.

"The data forced me to change my opinion. We now know that twins are not twice the risk of singletons, they are more like four times the risk. For instance, there is a 1 in 700 chance of cerebral palsy with a single birth, but 1 in 100 with twins. If you define success of a pregnancy as a healthy baby and a healthy mother, it's safer to reduce to singleton. Women should be aware that this is a possibility," he says.