About embryo transfers Number of embryos Risks Fresh vs. frozen

What is an embryo transfer?

Once a woman’s eggs are retrieved and fertilized, the next step in IVF is to transfer one or more of the resulting embryos to the woman’s uterus.

Our physicians guide a fine-point catheter with the embryos through the vagina and cervix into the uterus, where the embryos are deposited. Originelle is the first centre to introduce vaginal ultrasound guided embryo transfer in Canada. A sedative or anesthesia may be given to make the procedure more comfortable.

How many embryos should be transferred?

Single embryo transfer is generally recommended, but it may be advisable to transfer two or even three due to quality of the embryos, the woman's age, and any other factor that could negatively affect the success rate. 

Risks of embryo transfer

The biggest risk of the embryo transfer is the risk of multiple pregnancy (twins, or even triplets). Multiples pregnancy and births put the babies at risk for low-birth weight or premature birth. 

Other risks may include:

  • Loss of the embryos/failed IVF cycle
  • Embryo implanting in the fallopian tubes
  • Cramping during or after the procedure (although the procedure is usually pain-free)

Fresh versus frozen embryo transfer

Embryos used in IVF can be either fresh or frozen. A fresh embryo transfer (including stimulation, collection, and fertilization) is performed within one menstrual cycle whereas a frozen embryo transfer can be performed at a later time. 

There is no evidence that frozen embryo transfers are unsafe or lead to any higher incidence of birth defects or miscarriages.  Moreover, some research has shown that frozen embryo transfers are safer than fresh cycles for the mother and embryo because the woman’s body has a chance to rest after the ovulation induction cycle.