The transfer of two embryos instead of three to reduce the risk of multiple pregnancy: a retrospective analysis

J Assist Reprod Genet. 1999 Jan;16(1):1-5. doi: 10.1023/a:1022581225987.


Purpose: Our purpose was to investigate whether a reduction in the number of embryos transferred from three to two would help reduce the incidence of multiple pregnancies and yet leave the pregnancy rate unaffected.

Methods: Women were treated in a routine clinical in vitro fertilization program and the results analyzed retrospectively.

Results: There was no reduction in the pregnancy rate when two embryos were transferred compared with three. Indeed, there was actually an increase in pregnancy rate after the transfer of two embryos in those cases with one or more embryos remaining after the transfer.

Conclusions: The transfer of only two embryos compared to three in women younger than 40 years of age does not compromise the chance of pregnancy. Triplets were not seen in the limited series of patients when only two embryos were transferred, but the incidence of twins remained the same. Further consideration should be given to strategies that enable the transfer of single embryos without compromising the pregnancy rate.

MeSH terms

  • Adult
  • Embryo Transfer*
  • Female
  • Fertilization in Vitro*
  • Humans
  • Infertility, Female / therapy
  • Pregnancy
  • Pregnancy Outcome
  • Pregnancy Rate
  • Pregnancy, Multiple*
  • Retrospective Studies
  • Triplets
  • Twins