North America

Professional organisations in both Canada and the United States have recommended a wider adoption of single embryo transfer (SET).

Canada

• Policy
  There is currently no state regulation. In 2003, only 10% of cycles were SET: in 55% of cycles, 2 embryos were transferred and in 27% of cycles, 3 embryos were transferred. Older women (average age 39) received more embryos.

        Only one province partially covers the costs of Assisted Human Reproduction (AHR) procedures,
        and this is only when a woman’s fallopian tubes are fully blocked.

        In 2006, the Society of Obstetricians and Gynaecologists of Canada (SOGC) and Canadian Fertility
        and Andrology Society (CFAS) jointly released guidelines for the number of embryos to transfer
        following IVF. These advise transferring no more than 2 embryos in fresh cycles for women under
        35. For those in this age group with an excellent chance of pregnancy, SET should be considered.

        New regulations covering the number of embryos transferred are currently under review, and there
        is a significant focus on reducing multiple births. Under the new rules embryo transfer is intended to
        be subject to regulation – at present it is a matter of voluntary compliance.

• Result
  In the years 1999–2005, an average of 30% of all births that resulted from AHR were multiple. It is hoped that the new regulations will reduce this rate.

        For updates to regulations, see the
        Assisted Human Reproduction Implementation Office (AHRIO) website. 

        For all laws and regulations, see the Department of Justice website. 
          
        For more information, see also the SOGC website and the CFAS website.

United States

• Policy
  There is no state regulation, but 1999 Guidelines by the American Society of Reproductive Medicine (ASRM) advise that no more than 2 embryos should be transferred for women who were most likely to become pregnant, and no more than 5 for patients with a lesser chance of pregnancy.

         In 2006, in an effort to further reduce the incidence of high-order multiple pregnancies, ASRM
         and the Society for Assisted Reproductive Technology (SART) developed guidelines to assist
         ART programs and patients in determining the appropriate number of cleavage stage 
         (usually 2–3 day) embryos or blastocysts (usually 5 or 6 days after fertilisation) to transfer.

         These guidelines recommended that women under 35 who are most likely to become pregnant
         should be encouraged to consider single embryo transfer; those aged 35–37 with a good chance
         of becoming pregnant should receive no more than 2 embryos; those aged 38–40 with a good 
         chance of becoming pregnant should receive no more than 3 cleavage stage embryos or no
         more than 2 blastocysts. Older patients and those who are less likely to become pregnant 
         may have more embryos transferred.

         For details, see http://www.asrm.org/Media/Practice/NoEmbryosTransferred.pdf.

• Result
  In recent years there has been a downward trend in triplets and other multiple births, but the number of twins seems to continue to rise. Fetal reduction may have played a role in reducing the actual number of babies born from multiple pregnancies.