- In each of the above age groups, patients who do not meet criteria for a favourable prognosis may have an additional embryo transferred according to individual circumstances. The patient must be counselled regarding the additional risk of twin or higher-order multiple pregnancy.
- If otherwise favourable patients fail to conceive after multiple cycles with high-quality embryo(s) transferred, physicians and patients may consider proceeding with an additional embryo to be transferred.
- Patients with a co-existing medical condition for which a multiple pregnancy may increase the risk of significant morbidity should not have more than one embryo transferred.
- In the rare cases where the number of embryos or blastocysts transferred exceeds recommended limits, both the counselling and the justification must be documented in the patient’s permanent medical record.
- In women ≥43 years of age, there are insufficient data to recommend a limit on the number of embryos to transfer when the patient uses her own oocytes. Caution should be exercised as the risk associated with multiple pregnancy increases dramatically with advancing maternal age.
In Donor-Oocyte Cycles
In donor-oocyte cycles, the age of the donor should be used to determine the appropriate number of embryos to transfer. For example, when the donor is <35 years of age and other favourable criteria exist, single-embryo transfer should be planned.
In Frozen Embryo Transfer Cycles
In frozen-embryo transfer cycles, favourable characteristics should be based on the age of the woman when the embryos were frozen and include the presence of high-quality vitrified embryos, euploid embryos, first FET cycle, or previous live birth after an IVF cycle. Embryo transfer numbers should not exceed the recommended limit on the number of fresh embryos transferred for each age group.