Twins in Demand Through IVF?
Despite some couples' desires, doctors counsel against trying for twins through in vitro fertilization.
Medical Risks of Multiple Births continued...
Of course, many twins are born on time and are healthy.
For instance, while the infant death rate among twins is much higher than the rate for single babies, the vast majority of infant twins don't die. CDC records show that about 30 out of 1,000 U.S. twins born in 2006 died during infancy, compared to six per 1,000 single babies.
So it's not that all twins are headed for complications. But their odds aren't as good as single babies.
"The good news is that most of the time with twins, and maybe even with triplets, people end up with normal, healthy babies. But there are significant number of bad outcomes," says Peaceman.
And those bad outcomes become more common with increasing numbers of babies. So twins are riskier than single babies, but less risky than triplets, quadruplets, or more.
Because of the relative risks, most doctors discourage trying for twins or other multiples.
"Anybody who comes in asking for multiple births, we will dissuade and try to get them thinking correctly," Perloe says. Muasher says he tells his patients that "the best outcome that I would like to hope for is to have one healthy baby."
Doctors can't guarantee twins at the onset of IVF, anyway. SART and the American Society of Reproductive Medicine (ASRM) have guidelines about how many embryos should be transferred to an IVF patient, based on her age, reproductive history, and embryo quality. But not all embryos that are transferred result in live births, and even if only one embryo is transferred, that embryo could split, leading to twins.
In short, the outcome of IVF isn't totally within the patient's or doctor's control.
The risk of premature birth is the top concern for Phyllis Dennery, MD, FAAP. As chief of the neonatology division at Children's Hospital of Philadelphia, she sees firsthand the complications that can occur with twins and other multiples.
Dennery explains that the more embryos there are in a uterus, the greater the chance of preterm birth and its complications, such as immature lungs, brain, gut, and bleeding in the brain.