Canadian obstetrics and fertility societies publish joint guidance concerning the number of embryos that should be transferred following IVF.
The Society of Obstetricians and Gynecologists of Canada and the Canadian Fertility and Andrology Society have published joint guidelines for the number of embryos to transfer following IVF.

The guidelines extrapolate from a review of English-language articles listed in the Cochrane Library and MEDLINE from 1990 to April 2006, along with references identified from the bibliographies of the primary articles.

The collaborators write: “This guideline is intended to minimize the occurrence of multifetal gestation, particularly high-order multiples, while maintaining acceptable overall pregnancy and live birth rates following IVF-embryo transfer.”

Among the 13 recommendations, the guidelines state that individual programs should look at their own data to identify determinants of implantation and live birth rates and develop their optimal embryo transfer policies.

In general, fewer blastocyst-stage than cleavage-stage embryos should be transferred, particularly in women with both “excellent” prognoses and high-quality embryos, the guidelines state.

The authors explain: “Women with excellent prognoses include those undergoing their first or second IVF-ET cycle or one immediately following a successful IVF-ET cycle, with at least two high-quality embryos available for transfer.”

The collaborators say no more than two fresh embryos should be transferred in women under 35 years of age, and those with “excellent prognoses” are candidates for single embryo transfer.

No more than three embryos should be transferred in women aged 38-29 years, and no more than four in patients over 39 years of age.