95 out of 100 do not survive

The most ethically contentious issue in the IVF industry is the destruction
of embryos. But how many are being destroyed is difficult to assess. A recent
study in the US journal Fertility and Sterility by researchers at Yale
University School of Medicine offers an answer. It appears that of every 100
eggs fertilised in an IVF laboratory, only 5 will become live births. In other
words, 95% of all IVF embryos are discarded, perish in the Petri dish or die in
the womb.

What explains the "dramatically low oocyte to baby rate"? The first losses
occur at fertilisation. Only about 31% of the fertilised eggs become usable for
transfer or freezing. One reason could be that only a few of the oocytes
retrieved after ovarian stimulation are actually viable. Another reason may be
that the culture medium in which the embryos are nurtured adversely affects
their ability to develop.

The researchers conclude that more is not better in IVF. It is not the number
of eggs retrieved that counts, but their quality. In fact, in women over 40,
only 1 in 100 embryos becomes a live birth. "Our data show that an overwhelming
majority of oocytes retrieved, fertilized, and fully utilized do not result in
the birth of a baby and are thus wasted," the authors write. ~ Fertility
and Sterility, April