Two IVF Embryos Are No More Likely to Produce a Baby Than One

By Tiffany Sharples

As the case of the so-called Octomom continues to spur outrage and debate over the use of in vitro fertilization (IVF) in the U.S., new research suggests that the most effective and inexpensive IVF method may also be the least likely to result in dangerous multiple births.

A study by Finnish researchers published in the current issue of the journal Human Reproduction finds that transferring a single fresh embryo at a time, followed by subsequent transfers of individual thawed embryos, may be as effective in achieving pregnancy as implanting multiple embryos at once. Using one embryo at a time also cuts medical costs, the study found, saving about $27,000 per live birth pregnancy.

"Elective single embryo transfer is the better option under most scenarios," says Dr. Zdravka Veleva, one of the study's authors and a faculty member of the department of obstetrics and gynecology at Finland's University of Oulu. The findings reflect what U.S. fertility doctors say they are seeing increasingly in their own practices. (Read "Building a Better Baby: A New In Vitro Test.")

Veleva's study compared outcomes of treatments during two periods at the university's fertility clinic: between 1995 and 1999, when double embryo transfer was used much more commonly than single embryo transfer, which was performed for just 4.2% of cases, and between 2000 and 2004, when 46.2% of women opted for elective single embryo transfer. (The increase in single embryo transfers reflects, in part, changing attitudes in Europe toward using multiple embryos.) In both time periods, the study found, 90% of women delivered babies within their first four treatment cycles, regardless of how many embryos were implanted. That suggests no advantage of multiple-embryo implantation and no delay in pregnancy from using one embryo at a time. Additionally, the incidence of multiple births was halved between the two periods.

Unlike many previous studies, which have looked only at the success rates of individual fresh embryo transfers, the current study also considered the cumulative success rate for all embryos created and implanted from a single harvesting of eggs — including those that had been frozen. Researchers found that the total pregnancy rate per egg retrieval was higher when embryos were implanted individually. For each "ovum pickup" the overall pregnancy rate was 38% among women who had elective single embryo transfers, and 33% among those who had more than one embryo implanted.

Some of that success can be attributed to improvements in freezing techniques...Read more...  

Source: TIME