"And so now everyone knows that high-tech fertility treatment has the ability to produce twins, triplets, or even eight babies all at the same time," said Dr. Richard Paulson, professor of reproductive medicine at USC.
Implanting that many embryos is unethical. Paulson says U.S. fertility specialists may implant anywhere from two to four embryos based on a woman's medical history.
But a new study in the British Medical Journal suggests implanting one embryo at a time is sufficient and may be just as successful as implanting two at the same time.
"Whether you transfer the two embryos at one time, or you transfer one now and another one and a month later, the success seems to be the same," said Paulson.
Paulson says that may make sense in the United Kingdom, where fertility treatments are covered by insurance. But in California, patients pay out of pocket.
"Everyone is quite motivated to make the success rate be as high as possible, and they're actually willing to have twins -- they would like to have twins, that's a good outcome for them," said Paulson.
While some couples want twins, the complication rate of carrying multiples is much higher than a single birth, especially for women in their late 30s and 40s. The study proves single embryo transfers can work and that embryo freezing is a viable option. But when it comes down to it, the choice should be ultimately up to the patient.
"We are much more reluctant to tell patients you have to do this or you have to do that. We really offer choices and that's really what assisted reproduction is about," said Paulson.
Women in the study were mostly young, so experts say the results reported here may not be applicable to women who have greater difficulty conceiving, have medical conditions, or are older.