A zygote is a newly fertilised egg, before cell division has started to take place. With ZIFT, fertilisation occurs in the laboratory just as it does in IVF. The difference is that the newly fertilised eggs are transferred much sooner than they would be with IVF.
Up to three pre-embryos can be transferred at one time to the woman’s fallopian tube under general anaesthetic.
The reasoning behind this procedure is that the natural environment of the body is a
better place to encourage an embryo to develop than a laboratory dish.
ZIFT is not a much-favoured technique any more as its main disadvantage is that the woman has to undergo two invasive procedures – egg collection and then zygote transfer – in quick
succession. Also, the opportunity to select the best three embryos to transfer is lost, as
when the zygotes are transferred it is impossible to tell which of the fertilised eggs are
developing most promisingly.
